Full opinion text
RANDALL, Circuit Judge; This appeal essentially involves an all-out assault by two unions and other related parties on the so-called “double breasted” system of conducting business utilized by contractor employers in the construction business in the New Orleans area. Hotly contested causes of action are alleged under several legal theories, primarily pursuant to the federal labor and antitrust laws; the district court dismissed all claims against the many defendants involved in this action. As explained more fully infra, we affirm the dismissal of certain claims, reverse the dismissal of others, and remand to the district court for further proceedings and development of a more complete factual record. I. FACTUAL AND PROCEDURAL BACKGROUND. This lawsuit was brought by Carpenters Local Union No. 1846 and Piledrivers Local Union No. 2436 of the United Brotherhood of Carpenters and Joiners of America, AFL-CIO (hereinafter “Unions”), both unincorporated labor organizations engaged in representing construction employees within the jurisdiction of the United States District Court for the Eastern District of Louisiana. Also party plaintiffs in the suit are three employee benefit funds established on the basis of various collective bargaining agreements between the Unions and signatory employers in the construction industry: the Carpenters District Council of New Orleans and Vicinity Pension Trust, the Carpenters District Council of New Orleans and Vicinity Health and Welfare Plan, and the Carpenters District Council of New Orleans and Vicinity Apprenticeship, Educational and Training Program (hereinafter “Funds”). Additionally, the suit was brought as a class action on behalf of proposed classes of all members of and all persons seeking employment through the Unions and all participants and beneficiaries of the named Funds. No class has at present been certified by the district court. Four defendants were named: PrattFarnsworth, Inc. (“Farnsworth”); Halmar, Inc. (“Halmar”); Associated General Contractors of Louisiana, Inc., New Orleans District (“AGC-New Orleans”); and Associated General Contractors of Louisiana, Inc., At Large District (“AGC-At Large”). The Associated General Contractors, Inc., is a trade organization consisting of various construction companies throughout Louisiana. It is divided administratively into several geographic districts. AGC-New Orleans is one of those districts. AGC-At Large is not limited to any geographical area. Farnsworth is a construction company in the New Orleans area and a member of AGC-New Orleans. Halmar is also a construction company in New Orleans and a member of AGC-At Large. One of AGC-New Orleans’ activities is the negotiation, on behalf of certain of its members, of collective bargaining agreements with local trade unions. AGC-New Orleans is not itself a signatory to these bargaining agreements; rather, the agreements are signed only by the member and non-member contractors who wish to be bound. In the instant case, AGC-New Orleans negotiated a collective bargaining agreement between a multiemployer bargaining unit and the Unions covering the period from May 1, 1977 to April 30, 1980. This agreement constitutes the controverted subject matter of this suit. Defendant Farnsworth affiliated itself with the AGC organizations, and authorized AGC-New Orleans to bargain on its behalf with the Unions over wages, terms, and conditions of employment. Farnsworth is a signatory to the collective bargaining agreement negotiated by AGC-New Orleans and the Unions. AGC-New Orleans, AGC-At Large, and Halmar are not signatories to the collective bargaining agreement. In their complaint, plaintiffs have alleged causes of action under three different sets of federal statutes, namely, (1) section 301(a) of the Labor Management Relations Act, 29 U.S.C. § 185(a) (hereinafter “LMRA”); (2) the Employee Retirement Income Security Act, 29 U.S.C. §§ 1001— 1461 (hereinafter “ERISA”); and (3) the Sherman and Clayton Antitrust Acts, 15 U.S.C. §§ 1-7, 12-27. Multiple allegations were made by the plaintiffs under each of these statutory causes of action. First, the plaintiffs alleged violations of the antitrust laws. The gravamen of their antitrust complaint is that the four defendants have conspired to restrain competition in the contractor services market in the New Orleans area by carving out an enclave of non-union carpentry work, access to which is denied union contractors in the industry. They contend that the effect of this alleged conspiracy is to nullify the multiemployer bargaining agreement between the Unions and the signatory contractors, and to coerce third parties in the construction industry to hire non-union contractors and subcontractors. The plaintiffs’ claims under section 301 of the LMRA echo their antitrust allegations. They allege that a “double breasted” operation exists between defendants Farnsworth and Halmar and is being used to channel construction work into Halmar, the non-union part of the operation, while operations of Farnsworth are being phased out slowly to the point of nonexistence. The plaintiffs argue that Farnsworth and Halmar should be treated as a single employer or as alter egos with the result that Halmar would be bound by the collective bargaining agreement that Farnsworth executed with the Unions. The ERISA cause of action is likewise interrelated with the section 301 labor action. The plaintiffs argue that Farnsworth and Halmar have breached the collective bargaining agreement by failing to submit fringe benefit contributions on behalf of their employees to the Funds as required by the agreement. Defendants moved for dismissal for failure to state a claim and in the alternative for dismissal for lack of subject matter jurisdiction and for summary judgment. Affidavits were attached to these motions. Plaintiffs thereafter filed a set of interrogatories addressed to the defendants. Before the defendants had filed any answers to the plaintiffs’ interrogatories, the district court granted the defendants’ motions to dismiss. Carpenters Local Union No. 1846 v. Pratt-Farnsworth, Inc., 511 F.Supp. 509 (E.D.La.1981). The district court held that AGC-New Orleans and AGC-At Large were not proper defendants to the section 301 labor claims and the ERISA claims because they had never signed the collective bargaining agreement with the Unions. Id. at 511-12, 514-15. The court dismissed the section 301 and ERISA claims against Farnsworth on the ground that the plaintiffs had never alleged any breach of the collective bargaining agreement on the part of Farnsworth in regard to its own employees. Id. at 512-15. As to Halmar, the court dismissed the section 301 and ERISA claims on the basis that it had no authority to determine that Farnsworth and Halmar were a single employer or alter egos without also determining the appropriate bargaining unit of their employees, which, it held, would be an impermissible invasion of the jurisdiction of the National Labor Relations Board (hereinafter “NLRB” or “the Board”). Id. at 512-13. Additionally, the court held that dismissal of the section 301 and ERISA claims as to all defendants was required because of the plaintiffs’ failure to exhaust the contractual grievance procedures provided in the collective bargaining agreement. Id. at 513-15. Finally, the district court dismissed the antitrust allegations because it decided that the bargaining agreement fell within certain nonstatutory exemptions to the antitrust laws, and that the plaintiffs’ causes of action were in reality labor law issues parading as antitrust claims. Id. at 512-22. The plaintiffs have appealed to this court, contesting the district court’s dismissal on all claims as to all defendants. Our task now is to determine whether the district court acted properly in dismissing the plaintiffs’ claims. Except with respect to the question of exhaustion of contractual grievance procedures, we treat the district court’s actions as dismissals under Rule 12(b)(6). In our review of those claims dismissed under Rule 12(b)(6), we may not go outside the pleadings; we must accept all well pleaded facts as true and view them in the light most favorable to the plaintiffs. Dike v. School Board, 650 F.2d 783, 784 (5th Cir. 1981); Brett v. First Federal Savings & Loan Association, 461 F.2d 1155 (5th Cir. 1972). We cannot sustain the district court’s dismissal for failure to state a claim “unless it appears beyond doubt that the plaintiff can prove no set of facts in support of his claim which would entitle him to relief.” Conley v. Gibson, 355 U.S. 41, 45-46, 78 S.Ct. 99, 101-102, 2 L.Ed.2d 80 (1957). The district court did go beyond the pleadings in addressing the question of exhaustion of contractual grievance proceedings, and thus we will review its dismissal on that ground as a grant of summary judgment. Our review in that case involves the questions (1) whether there are any issues of material fact in dispute, and if not (2) whether the moving party is entitled to judgment as a matter of law. Daly v. Sprague, 675 F.2d 716 (5th Cir. 1982); Impossible Electronics Techniques, Inc. v. Wackenhut Protective Systems, Inc., 669 F.2d 1026, 1030-31 (5th Cir. 1982). II. THE SECTION 301 ALLEGATIONS. A. Section SOI Claims Against' AGC-New Orleans and AGC-At Large. Pursuant to section 301(a) of the LMRA, 29 U.S.C. § 185(a), federal courts have jurisdiction to examine alleged violations of collective bargaining agreements: Suits for violation of contracts between an employer and a labor organization representing employees in an industry affecting commerce as defined in this chapter, or between any such labor organizations, may be brought in any district court of the United States having jurisdiction of the parties, without respect to the amount in controversy or without regard to the citizenship of the parties. 29 U.S.C. § 185(a). A section 301 claim must satisfy three requirements: (1) a claim of violation of (2) a contract (3) between an employer and a labor organization. E.g., Alvares v. Erickson, 514 F.2d 156, 161 (9th Cir.), cert. denied, 423 U.S. 874, 96 S.Ct. 143, 46 L.Ed.2d 106 (1975). The plaintiffs concede that the two AGC defendants did not sign the collective bargaining agreement at issue in this case and therefore are not contractually bound by it. Nonetheless, the plaintiffs argue that a section 301 claim properly lies against the two AGC defendants because Farnsworth and Halmar breached the bargaining agreement, and the two AGC defendants conspired to effect that breach and actively encouraged it. The district court held that “[t]he absence of [a] contractual relationship between AGC, New Orleans or AGC, At Large and Carpenters District Council mandates dismissal as to them of the Section 301 claim under settled authority in this jurisdiction.” 511 F.Supp. at 512 (emphasis in original). The plaintiffs contend that the absence of a contractual relationship between the two AGC defendants and themselves should not be regarded as fatal to the section 301 claims; rather, the plaintiffs argue that section 301 jurisdiction exists to assert a cause of action against a defendant whenever the object of the suit is the enforcement of rights guaranteed by a collective bargaining agreement in effect between an employer and a labor organization. In support of this contention, the plaintiffs cite three cases: Smith v. Evening News Association, 371 U.S. 195, 83 S.Ct. 267, 9 L.Ed.2d 246 (1962); Rehmar v. Smith, 555 F.2d 1362 (9th Cir. 1977); Alvares v. Erickson, supra. These three cases are inapposite. In all of these cases, the issue was whether section 301 causes of action encompassed suits by individual union employees for the enforcement of rights guaranteed by a collective bargaining agreement entered into by their unions. We note, however, that support for the plaintiffs’ contention may be found in a recent decision by the Third Circuit. In Wilkes-Barre Publishing Co. v. Newspaper Guild Local 120, 647 F.2d 372 (3d Cir. 1981), cert. denied, 454 U.S. 1143, 102 S.Ct. 1003, 71 L.Ed.2d 295 (1982), the court stated that “so long as the obligation sought to be enforced has its source in the provisions of a collective bargaining agreement, remedies for its enforcement may be available under section 301(a) in suits other than on the contract itself.” Id. at 380. Thus, the court determined that a federal court has jurisdiction over a section 301 suit brought against a non-party to a collective bargaining agreement who allegedly induces a party to breach the agreement. Id. at 376-81. In making this determination, the court stated that “what emerges as the law of [this] circuit as to the meaning of section 301(a) is that it reaches not only suits on labor contracts, but suits seeking remedies for violation of such contracts.” Id. at 380 (emphasis in original). The court reasoned that protection against tortious interference with a collective bargaining agreement involves protection of a property interest which has its source in the federal common law of labor contracts. Id. at 381. In addition, the court reasoned that the issue in such cases is not the nature of the remedy sought for an alleged violation of a collective bargaining agreement, but whether the remedy requires that the court from which it is sought interpret the agreement. Id. at 380. Notwithstanding the Third Circuit’s decision in Wilkes-Barre, courts have almost unanimously held that a section 301 suit may be brought for violation of a labor contract only against those who are parties to the contract at issue. Aacon Contracting Co. v. Association of Catholic Trade Unionists, 276 F.2d 958 (2d Cir. 1960), aff’g and adopting 178 F.Supp. 129, 130 (E.D.N.Y.1959); Haspel v. Bonnaz, Singer & Hand Embroiderers Local 66, 216 F.2d 192 (2d Cir. 1954), aff’g and adopting 112 F.Supp. 944, 945 (S.D.N.Y.1953); Fabian v. Freight Drivers Local 557, 448 F.Supp. 835, 838 (D.Md.1978); Cate v. Blue Cross & Blue Shield, 434 F.Supp. 1187, 1189 (E.D.Tenn.1977); Beausoleil v. United Furniture Workers, Local 136-B, 244 F.Supp. 719, 720 (D.N.H.1965). Indeed, this latter view has also been followed by a district court in our own circuit in a decision cited as controlling by the district court in the instant case. In Dixie Machine Welding & Metal Works, Inc. v. Marine Engineers Beneficial Association, 243 F.Supp. 489 (E.D.La.1965), a plaintiff employer brought suit in state court to enjoin the defendant union’s picketing. The union obtained removal to federal district court on the ground that the proceeding was a section 301 action; it had argued that because the suit was based in part on the alleged breach of a collective bargaining agreement between the plaintiff employer and various labor organizations, it arose under section 301. Writing the opinion in Dixie Machine Welding, our late colleague and then-district court judge, Robert A. Ainsworth, Jr., held that the plaintiff’s case was improvidently removed to federal court and that the district court had no jurisdiction to hear the case. Judge Ainsworth noted that although a collective bargaining agreement existed between the plaintiff employer and its employees, no such agreement existed between the plaintiff employer and the Marine Engineers Beneficial Association, the defendant in the case. As a result, he concluded that this was not a suit for violation of a contract between an employer and a labor organization as required by section 301: While it is alleged by plaintiff that the activity of its employees (resulting from their refusal to cross the picket line of defendant) is being carried on in violation of the collective bargaining agreements between plaintiff and its employees, this suit is not against plaintiff’s employees but against Marine Engineers Beneficial Association with which plaintiff has no agreement of any kind. Between the parties to this action, therefore, there is no collective bargaining agreement and this is not a “suit for violation of contracts between an employer and a labor organization” or between labor organizations which under Section 301 of the Labor Management Relations Act would confer jurisdiction in this court. 243 F.Supp. at 491 (emphasis in original). The Unions attempt to circumvent the logic of the Dixie Machine Welding case, supra, by arguing that while no agreement exists between the two AGC defendants and themselves on which to base jurisdiction, the AGC defendants have nevertheless conspired to breach the agreement in effect between Farnsworth and the Unions. We must reject this argument. A conspiracy to violate a collective bargaining agreement does not, without more, state a cause of action under section 301 sufficient to confer jurisdiction on a federal court. Kaylor v. Crown Zellerbach, Inc., 643 F.2d 1362, 1368 (9th Cir. 1981); Russom v. Sears, Roebuck & Co., 558 F.2d 439, 441 n.3 (8th Cir.), cert. denied, 434 U.S. 955, 98 S.Ct. 481, 54 L.Ed.2d 313 (1977); Abrams v. Carrier Corp., 434 F.2d 1234, 1253-54 (2d Cir. 1970), cert. denied sub nom. United Steelworkers v. Abrams, 401 U.S. 1009, 91 S.Ct. 1253, 28 L.Ed.2d 545 (1971); Aacon Contracting Co. v. Association of Catholic Trade Unionists, supra; Berard v. General Motors Corp., 493 F.Supp. 1035, 1042 (D.Mass.), aff’d mem., 657 F.2d 261 (1st Cir. 1980), cert. denied, 451 U.S. 987, 101 S.Ct. 2322, 68 L.Ed.2d 845 (1981). In conclusion, we must agree with the district court that the absence of a contractual relationship between AGC-New Orleans or AGC-At Large and the Unions requires dismissal of the section 301 claim against the two AGC defendants. B. Section 301 Claims Against Farnsworth. As stated before, a section 301 claim must satisfy three requirements before it may be asserted in federal court: (1) a claim of violation of (2) a contract (3) between an employer and a labor organization. 29 U.S.C. § 185(a). All three of these requirements appear to be met with respect to defendant Farnsworth. Both the plaintiffs and the defendants in this action concede that Farnsworth signed the collective bargaining agreement with the Unions and that Farnsworth is an employer of the Unions’ membership; moreover, the original complaint filed by the plaintiffs alleged that Farnsworth had violated the collective bargaining agreement. The district court apparently never considered the plaintiffs’ section 301 claims against Farnsworth separately and apart from their section 301 claims against Hal-mar, presumably because of the allegation that Farnsworth and Halmar were alter egos who were both liable for violation of the collective bargaining agreement. However, the pleadings offered by both the Unions and the Funds allege simply that “defendants” have obligated themselves to make employee contributions, and this implies that not only Farnsworth qua Halmar but Farnsworth qua Farnsworth may be in breach of its obligations. Having stated such a claim for relief, we think that the plaintiff Unions and Funds should have at least been given an opportunity to prove that Farnsworth refused to pay contributions on behalf of those employees who no one contests are Farnsworth’s own. Thus we cannot sustain a 12(b)(6) dismissal with respect to Farnsworth and must remand for consideration on the merits of this breach of contract claim. C. Section 301 Claims Against Halmar. The Unions’ and Funds’ section 301 claims against Halmar present a much more difficult problem. The plaintiffs are suing Halmar for its alleged violation of the collective bargaining agreement executed between the Unions and Farnsworth. Unlike Farnsworth, however, Halmar never signed the collective bargaining agreement; therefore, unless the plaintiffs can establish an alternative ground for holding Halmar to the agreement, Halmar must be treated the same as the nonsignatory AGO defendants, and we must affirm the district court’s dismissal of the section 301 claims against Halmar. The relevant portions of the plaintiffs’ complaint allege first, that Farnsworth and Halmar “are and at all times material herein have been affiliated business enterprises, with common ownership and management, centralized control of labor relations, sharing of equipment and other assets, and employees and they constitute a single integrated business enterprise, doing business within the geographic jurisdiction of the Court, and constituting a single employer for all purposes relevant thereto;” and second, that “[djuring the terms of the collective bargaining agreement between the AGC and Carpenters District Council, described as the ‘Craft Agreement’, defendant employer Pratt-Farnsworth conspired with the knowledge and assent of the AGC and unknown labor persuaders (29 U.S.C. § 433(b)) to establish and operate Halmar in order to circumvent and evade the Craft Agreement provisions and create a union-free environment.” 1 Rec. 3, 5. As will be developed later, the first of these two theories, when applied by the Board in the context of an unfair practice charge under the National Labor Relations Act, 29 U.S.C. §§ 151-168 (hereinafter “NLRA”), is known as the single employer doctrine, and the second, when so applied by the Board, is known as the alter ego doctrine. The plaintiffs, therefore, urge this court to hold that they have stated a claim, under section 301 of the LMRA, for breach of the terms of a collective bargaining agreement by Halmar, a non-signatory to that agreement, on the basis of the single employer theory or the alter ego theory developed by the Board in unfair labor practice cases under the NLRA. Before progressing any further with the arguments advanced by the plaintiffs in support of their position that they have stated a claim under section 301, or the arguments advanced by the defendants against that position, it would be helpful to describe the origins and content of these two theories. 1. Single Employer Doctrine. The single employer doctrine is a creation of the Board which allows it to treat two or more related enterprises as one employer within the meaning of section 2(2) of the NLRA, 29 U.S.C. § 152(2). Often the doctrine is invoked to combine the amount of business of two or more employers so that the whole will exceed the Board’s self-imposed jurisdictional minimum. E.g., Radio & Television Broadcast Technicians Local Union 1264 v. Broadcast Service of Mobile, Inc. (Radio Union), 380 U.S. 255, 256, 85 S.Ct. 876, 877, 13 L.Ed.2d 789 (1965) (per curiam), quoted with approval in South Prairie Construction Co. v. Local No. 627, International Union of Operating Engineers (Peter Kiewit), 425 U.S. 800, 802 n.3, 96 S.Ct. 1842, 1843 n.3, 48 L.Ed.2d 382 (1976). The doctrine is not, however, limited to use only as a jurisdictional tool. The finding that two entities are a single employer may have the consequence of treating them as one for purposes of considering the existence of an unfair labor practice in a proceeding before the Board. E.g., Hageman Underground Construction, 253 N.L.R.B. 60 (1980) (certain respondents constituted a single employer for purposes of NLRA; backhoe operators employed by such respondents constituted a single appropriate unit; such respondents violated sections 8(a)(5) and (1) of the NLRA, 29 U.S.C. §§ 158(a)(5), (1), by refusing to recognize and bargain with the union as the exclusive representative of the employees in such unit and by failing to abide by the terms of the collective bargaining agreement covering such employees). The factors which the Board uses to determine the existence of single employer status are (1) interrelation of operations, (2) common management, (3) centralized control of labor relations, and (4) common ownership. Radio Union, supra, 380 U.S. at 256, 85 S.Ct. at 877; NLRB v. Don Burgess Construction Corp., 596 F.2d 378, 384 (9th Cir.), cert. denied, 444 U.S. 940, 100 S.Ct. 293, 62 L.Ed.2d 306 (1979); Sakrete, Inc. v. NLRB, 332 F.2d 902, 905 (9th Cir. 1964), cert. denied, 379 U.S. 961, 85 S.Ct. 649, 13 L.Ed.2d 556 (1965). As the court noted in Don Burgess, supra: The Board has stressed the first three of these factors, as well as the presence of control of labor relations. [Sakrete, Inc., supra ] at 905 n.4 (quoting with approval from NLRB Twenty-First Annual Report at 14-15). However, no one of the factors is controlling, NLRB v. Welcome-American Fertilizer Co., 443 F.2d 19, 21 (9th Cir. 1971), nor need all criteria be present. Single employer status . ultimately depends on “all the circumstances of the case” and is characterized as an absence of an “arm’s length relationship found among unintegrated companies.” Local 627, International Union of Operating Engineers v. NLRB, 171 U.S.App.D.C. 102, 107-108, 518 F.2d 1040, 1045-46 (1975), aff’d on this issue sub nom. South Prairie Construction Co. v. Local 627, International Union of Operating Engineers, 425 U.S. 800, 96 S.Ct. 1842, 48 L.Ed.2d 382 (1976). 596 F.2d at 384. A finding of single employer status does not by itself mean that all the subentities comprising the single employer will be held bound by a contract signed only by one. Instead, having found that two employers constitute a single employer for purposes of the NLRA, the Board then goes on to make a further determination whether the employees of both constitute an appropriate bargaining unit. As the Ninth Circuit stated in Don Burgess, 596 F.2d at 386, even if two firms are a single employer, a union contract signed by one would not bind both unless the employees of both constituted a single bargaining unit. The Ninth Circuit then explained the difference between an inquiry into single employer status and an inquiry into the appropriateness of the bargaining unit: In determining the appropriateness of a bargaining unit the focus differs from that employed in deciding whether there is a single employer. “In determining whether a single employer exists we are concerned with the common ownership, structure, and integrated control of the separate corporations; in determining the scope of the unit, we are concerned with the community of interests of the employees involved.” Peter Kiewit Sons’ Co., 231 N.L.R.B. 76, 77 (1977). 596 F.2d at 386. See Soule Glass and Glazing Co. v. NLRB, 652 F.2d 1055, 1075 n.8 (1st Cir. 1981). Under the single employer doctrine, the focus is the interrelatedness of the employers, while in assessing an appropriate bargaining unit, the focus is on the similarity of concerns between employees. See NLRB v. J. C. Penney Co., 559 F.2d 373, 375 (5th Cir. 1977) (“To [create a viable bargaining unit], the Board looks to such factors as bargaining history, operational integration, geographic proximity, common supervision, similarity in job function, and degree of employee interchange.”); NLRB v. Belcher Towing Co., 284 F.2d 118, 121 (5th Cir. 1960) (the test which the Board applies in determining whether a bargaining unit is appropriate is “community of interests”). To view it another way, we have stated in Local Union No. 59, International Brotherhood of Electrical Workers v. Namco Electric, Inc., 653 F.2d 143, 147 (5th Cir. 1981), that “[wjhether two firms are a single employer for collective bargaining purposes and whether a single contract is binding on two separate corporations are not only different questions, but they may have different answers.” 653 F.2d at 147. Whether they have different answers is a function of the appropriateness of the bargaining unit comprising the employees of both, firms. The Board has often applied or sought to apply the single employer-appropriate bargaining unit inquiries to double breasted contractors. Indeed, the case that receives the most attention in the briefs of the plaintiffs and defendants in this litigation— Peter Kiewit — is a case which began when a union filed a complaint with the Board alleging that two double breasted contractors had violated sections 8(a)(5) and (1) of the NLRA, 29 U.S.C. §§ 158(a)(5), (1) by their continuing refusal to apply to the employees of the non-union contractor the collective bargaining agreement in effect with the union contractor. We explore the case in some detail not only because it is an example of how the single employer doctrine functions in an unfair labor practice context, but also because, as we shall see later, a determination as to what the case holds — or does not hold — is important to a resolution of the problems before us. The union’s allegations in Peter Kiewit were that (1) the union contractor and the nonunion contractor were in reality a “single employer” and should be treated as such for the purpose of enforcing a collective bargaining agreement signed by the union contractor, and (2) because the two contractors were a single employer, the non-union contractor was obligated to recognize the union as the representative of a bargaining unit drawn to include both the non-union and the union contractors’ employees. 425 U.S. at 801, 96 S.Ct. at 1842. The NLRB found that the two contractors were separate employers and dismissed the complaint. Peter Kiewit Sons’ Co., 206 N.L.R.B. 562 (1973). On review, the District of Columbia Circuit held that the two contractors were in fact a single employer, finding “evidence [of] a substantial qualitative degree of interrelation of operations and common management” between the two companies. Local 627, International Union of Operating Engineers v. NLRB, 518 F.2d 1040, 1047 (D.C.Cir.1975). The circuit court then went on to decide the second issue presented by the union’s complaint, although the NLRB had not passed upon the bargaining unit question. The court held that the employees of the two contractors together constituted an appropriate unit for purposes of collective bargaining. Id. at 1047-50. On the basis of this conclusion, the court determined that the two contractors had committed an unfair labor practice by refusing to recognize the union as the bargaining representative of the nonunion contractor’s employees or to extend to them the terms of the collective bargaining agreement. Id. at 1050. On appeal, the Supreme Court affirmed the court of appeals’ determination on the single employer issue but vacated its holding that the employees of the two companies constituted an appropriate bargaining unit. 425 U.S. at 806, 96 S.Ct. at 1845. The Supreme Court held that the circuit court had invaded the statutory province of the NLRB by proceeding to decide the unit question before the NLRB had passed upon the issue: Since the selection of an appropriate bargaining unit lies largely within the discretion of the Board, whose decision, “if not final, is rarely to be disturbed,” we think the function of the Court of Appeals ended when the Board’s error on the “employer” issue was “laid bare”. Id. at 805-06, 96 S.Ct. at 1844-1845 (citations omitted). The Court then remanded the case to the NLRB for a determination of the bargaining unit issue. On remand, the NLRB decided that even though the two companies involved were a single employer, their employees together did not constitute an appropriate bargaining unit. Peter Kiewit Sons’ Co., 231 N.L.R.B. 76 (1977). The Board made clear in Peter Kiewit that the existence of union and non-union construction firms historically operated side by side by a single employer is not, without more, a violation of a collective bargaining agreement with the signatory construction firm. As the Board stated in its original Peter Kiewit decision, 206 N.L.R.B. 562 (1973): It is not uncommon in the construction industry for the same interests to have two separate organizations, one to handle contracts performed under union conditions and the other under nonunion conditions. The Board has recognized this fact by refusing to include the employees of a nonunion company in the same bargaining unit with those of a union company controlled by the same interests, and by refusing to require the nonunion company to recognize the bargaining representative of the union company’s employees or to apply the collective-bargaining contract with the latter to its own employees. (footnotes omitted). The Board gave as examples of this policy its decisions in Frank N. Smith Associates, Inc., 194 N.L.R.B. 212 (1971); Gerace Construction, Inc., 193 N.L.R.B. 645 (1971); and Central New Mexico Chapter, National Electrical Contractors Association, Inc., 152 N.L.R.B. 1604 (1965). See also A-1 Fire Protection Inc., 233 N.L.R.B. 38 (1977), enforced in part and remanded sub nom. Road Sprinkler Fitters Local Union No. 669 v. NLRB, 600 F.2d 918 (D.C.Cir.1979), on remand, 250 N.L.R.B. 217 (1980), remanded, 676 F.2d 826 (D.C.Cir.1982). The Supreme Court, remanding the case to the Board in its Peter Kiewit decision, did not purport to challenge this policy, noting only that a finding of single employer status does indeed require the additional determination that both the signatory’s and nonsignatory’s employees belong to the same bargaining unit before both entities will be bound by one agreement. See 425 U.S. at 805, 96 S.Ct. at 1844. It is clear that the primary motivation of the Board in making an independent unit determination in a single employer case is to protect the rights under section 7 of the NLRA, 29 U.S.C. § 157, of the employees of each of the subentities constituting the single employer to bargain collectively with representatives of their own choosing. Section 9(b) of the NLRA, 29 U.S.C. § 159(b), directs the Board to “decide in each ease whether, in order to assure to employees the fullest freedom in exercising rights guaranteed by [the NLRA], the unit appropriate for the purposes of collective bargaining shall be the employer unit, craft unit, plant unit, or subdivision thereof . . . . ” As the Supreme Court recognized in Peter Kiewit, supra, at 803-04, 96 S.Ct. at 1843-1844, and as we have set forth above, the factors leading to a single employer finding will not necessarily provide the assurance required by section 9(b) that the section 7 rights of the employees of the subentities involved will be adequately protected. That assurance is provided in an unfair labor practice case by the inquiry as to the appropriateness of the unit. Further, as will be shown in Part II.C.8 of this opinion, even the fact that the union employer and the union have stipulated in the agreement as to the appropriate unit will not preclude an inquiry by the Board into the appropriateness of the unit comprising the employees of both the union and nonunion employers. 2. Alter Ego Doctrine. As indicated above, the plaintiffs’ pleadings allege (in addition to interrelation of operations, common management, centralized control of labor relations and common ownership between Farnsworth and Halmar) that Halmar is being operated to circumvent and evade the obligations of Farnsworth under the collective bargaining agreement between Farnsworth and the Unions. This rationale, broadly read, echoes another Board-created doctrine, that of the alter ego employer. Alter ego issues commonly arise in successorship situations, when ownership of a signatory company changes hands. Although a bona fide successor is not in general bound by a prior collective bargaining agreement, an alter ego will be so bound. NLRB v. Tricor Products, Inc., 636 F.2d 266, 269-70 (10th Cir. 1980). This is because an employer will not be permitted to evade its obligations under the NLRA by setting up what appears to be a new company, but is in reality a “disguised continuance” of the old one. Southport Petroleum Co. v. NLRB, 315 U.S. 100, 106, 62 S.Ct. 452, 455, 86 L.Ed. 718 (1942). See also Howard Johnson Co. v. Detroit Local Joint Executive Board, 417 U.S. 249, 259 n.5, 94 S.Ct. 2236, 2242 n.5, 41 L.Ed.2d 46 (1974) (when “a mere technical change [is made] in the structure or identity of the employing entity, frequently to avoid the effect of the labor laws . . . the courts have had little difficulty holding that the successor is in reality the same employer and is subject to all the legal and contractual obligations of the predecessor.”). In deciding whether a company is an alter ego, the Board will often look to factors which bear some similarity to those involved in a single employer question; in particular, whether the two enterprises have substantially identical management, business purpose, operation, equipment, customers, supervision and ownership. Hageman Underground Construction, 253 N.L.R.B. 60 (1980); Crawford Door Sales Co., 226 N.L.R.B. 1144 (1976). However, the focus of the alter ego doctrine, unlike that of the single employer doctrine, is on the existence of a disguised continuance or an attempt to avoid the obligations of a collective bargaining agreement through a sham transaction or technical change in operations. E.g., Amalgamated Meat Cutters v. NLRB, 663 F.2d 223, 277 (D.C.Cir.1980) (sale of supermarket was not sham or “paper” transaction); NLRB v. Tricor Products, Inc., supra, at 270 (motivation by anti-union sentiment a relevant factor in alter ego analysis); NLRB v. Herman Brothers Pet Supply, Inc., 325 F.2d 68, 70-71 (6th Cir. 1963) (sale of store immediately after representation election was “a fictitious transaction to avoid dealing with the union and to discharge those employees who supported the union”); NLRB v. Ozark Hardwood Co., 282 F.2d 1, 5-7 (8th Cir. 1960) (Board was entitled to find that identity of structure and continuance of operations existed to support alter ego finding or could find successor to be an instrument of “evasion as to the labor-wrongs situation”). Further, an alter ego case frequently contains specific findings on the substantial continuity of the work force from the union to the non-union employer. E.g., Hageman Underground Construction, 253 N.L.R.B. 60, 68 (decision of Shapiro, A.L.J. 1980) (“All of the construction workers on the payroll of [signatory employer] were transferred to the payroll of [non-signatory employer], where they performed the same work which they had done while working for [signatory employer], using the same skills, and under the same immediate supervision.”); Crawford Door Sales Co., 226 N.L.R.B. 1144, 1150 (decision of Dyer, A.L.J. 1976) (“The number of employees was reduced by [signatory employer’s] unfair labor practices prior to the time [non-signatory employer] commenced business, but [non-signatory employer] continued the operations and the same employees with no discernible break.”). We have seen that the Board, in applying the single employer doctrine, makes an independent, careful investigation into whether the employees of two firms held to constitute a single employer constitute an appropriate bargaining unit. Only where the employees do constitute an appropriate unit will the non-signatory firm be bound to the collective bargaining agreement entered into between the signatory firm and the union. However, when the Board makes a finding that a non-signatory employer is the alter ego of a signatory employer which has voluntarily agreed to recognize the union’s representative status in a unit stipulated in the collective bargaining agreement, the Board generally will not reconsider the unit under the community of interests test, but will simply make a far more limited determination whether the stipulated unit is repugnant to any policy embodied in the NLRA. See Hageman Underground Construction, 253 N.L.R.B. 60, 70 (decision of Shapiro, A.L.J. 1980); Pioneer Inn Associates, 228 N.L.R.B. 1263, 1272 (decision of Shapiro, A.L.J. 1976) (“The salutary purpose of such agreement [as to the boundaries of an appropriate unit] would be frustrated if the parties were free to repudiate them at will and, thus, absent extraordinary circumstances or a clear denial of employees’ rights, the Board will not permit such repudiation, even where it would not have found the unit appropriate if the matter had been brought before it initially.”), enforced, 578 F.2d 835 (9th Cir. 1978). The Board’s reluctance to reexamine a stipulated unit in an alter ego case clearly stems from the fact that the conclusion that one employer is the alter ego of another is based on a holding that the two are in reality the same employer. 3. The District Court’s Decision. Having described the single employer and alter ego theories developed and applied by the Board, generally in the context of determining whether sections 8(a)(5) and (1) of the NLRA, 29 U.S.C. §§ 158(a)(5), (1), have been violated by the refusal of a non-signatory employer to abide by the terms of a collective bargaining agreement between a related signatory employer and the union, we turn to the district court’s decision in this case. The district court assumed that Peter Kiewit meant that a federal court was powerless to make an initial bargaining unit determination even in a section 301 suit, for it concluded that adoption of plaintiffs’ assertion that Farnsworth and Halmar are a single employer so as to make the instant labor contract binding upon Halmar necessarily would require a determination of the appropriate bargaining unit, and that such determination would be an invasion of the exclusive province of the N.L.R.B. not distinguishable from that condemned by the Supreme Court in the Peter Kiewit case. Hence, the motions to dismiss the Section 301 claims brought by Farnsworth and Halmar must be granted. 511 F.Supp. at 513 (emphasis in original). As a preliminary matter, we note that behind the district court’s reasoning lies the assumption that the pleadings allege only the single employer theory. But, as we have seen, the- pleadings also allege the alter ego theory as a basis for the Unions’ breach of contract action. Were we to accept the plaintiffs’ argument that they have stated a claim under section 301 employing the alter ego theory, and were we to hold that the district court should apply that theory in the same manner as the Board applies it in the unfair labor practice context, then, as described in Part II.C.2 above, a de novo determination of the appropriate bargaining unit might well not be necessary. Depending upon the proof, the district court might be able to limit itself to a consideration of whether the resulting unit is repugnant to the purposes of the NLRA, a far more limited inquiry. For the time being, we note only that the pleadings cannot be construed to allege only a single employer theory. 4. The Substantive Law to be Applied under Section 301. The district court’s determination is significant as much for its unstated premise as for its ultimate conclusion. That premise is that a district court, in an action for breach of contract under section 301 in which single employer status is alleged as a basis of recovery, would apply the single employer theory in the same fashion as it is employed by the Board in the unfair labor practice context. Under this approach, if the district court were to find that Farnsworth and Halmar were a single employer, a favorable determination as to the appropriateness of the bargaining unit consisting of the employees of both companies would be necessary before Halmar would be bound by the collective bargaining agreement entered into between the Unions and Farnsworth. Upon examination, we think that the district court’s premise was correct, and we would broaden it to include suits under section 301 based upon allegations of alter ego status as well. As the Supreme Court held in Textile Workers Union v. Lincoln Mills, 353 U.S. 448, 456, 77 S.Ct. 912, 917, 1 L.Ed.2d 972 (1957), the substantive law to be applied in suits under section 301 is federal law, “which the courts must fashion from the policy of our national labor laws.” It was Congress’ stated goal in adopting section 301 to treat collective bargaining agreements as contracts fully enforceable in federal courts, in order to encourage the making of such agreements and to promote industrial peace through faithful performance of such agreements. Id. at 453-54, 77 S.Ct. at 916. The NLRA similarly has as one of its goals the promotion of industrial peace through faithful performance of collective bargaining agreements. 29 U.S.C. § 151. We have seen that the Board has developed the single employer and alter ego theories in the context of unfair labor practice proceedings in which it is alleged that related employers have violated sections 8(a)(5) and (1) of the NLRA by failing to abide by the terms of a collective bargaining agreement entered into by one of them. Both of those theories are clearly designed to promote the faithful performance of a collective bargaining agreement not only by the signatory employer but also by a non-signatory employer with the requisite high degree of consanguinity to the signatory employer. Assuming that we can successfully negotiate the shoals of Peter Kiewit and its offspring, we see no reason why the law developed by the Board and by federal appellate courts in that context should not be the substantive law applied in a suit under section 301 against related employers for breach of a collective bargaining agreement entered into by one of them, at least for the purpose of deciding whether the plaintiffs have failed to state a claim under section 301. Indeed, in view of the common goals of the LMRA and the NLRA and the existence of a substantial body of case law developed by the agency possessing special expertise in the area, there is every reason why the substantive law should be the same. We recognize that the Board, in an unfair labor practice proceeding involving, e.g., single employer status, is operating under a statutory mandate (in section 9(b) of the NLRA) to determine whether the resulting unit is an appropriate unit and thereby to protect the section 7 rights of the employees involved. But we agree with the district judge that a district court in a section 301 case, although not operating under a specific statutory mandate such as section 9(b), should be similarly concerned about the section 7 rights of the employees. One of the principal policies of the national labor laws — that embodied in section 7 — is the protection of the exercise by workers of full freedom of association, self-organization, and designation of representatives of their own choosing for the purpose of negotiating the terms and conditions of their employment. 29 U.S.C. § 151. If, as the Supreme Court said in Lincoln Mills, 353 U.S. at 456, 77 S.Ct. at 917, we are to fashion the law under section 301 from the policy of our national labor laws, we cannot fail to honor and effectuate a policy so basic to those laws as the policy of protecting workers’ rights of free association. The defendants urge that the Unions have failed to state a claim under section 301 against Halmar simply because Halmar did not sign the collective bargaining agreement between Farnsworth and the Unions. But in order to accept this conclusion we would have to disregard the fundamental policies developed by the Board and by federal appellate courts in the unfair labor practice cases described in Parts II.C.l and 2 of this opinion. The rights of the Unions and the obligations of Farnsworth and Hal-mar would then depend upon the forum in which the claims were asserted. The Supreme Court addressed a similar problem in Howard Johnson Co. v. Detroit Local Joint Executive Board, 417 U.S. 249, 94 S.Ct. 2236, 41 L.Ed.2d 46 (1974), a suit brought by a union under section 301 to compel Howard Johnson to submit to arbitration to determine the extent of its obligations to the employees of a company whose assets Howard Johnson had purchased. Howard Johnson had specifically refused to assume the selling company’s collective bargaining agreement, which contained an arbitration clause. The district court nevertheless ordered Howard Johnson to arbitrate. The district court relied on the Supreme Court’s decision in John Wiley & Sons, Inc. v. Livingston, 376 U.S. 543, 84 S.Ct. 909, 11 L.Ed.2d 898 (1964), also a case under section 301 to compel arbitration; the court of appeals affirmed. Both the district court and the court of appeals recognized that the reasoning of Wiley was to some extent inconsistent with the Supreme Court’s later decision in NLRB v. Burns International Security Services, Inc., 406 U.S. 272, 92 S.Ct. 1571, 32 L.Ed.2d 61 (1972), but held that Wiley rather than Burns controlled. The two courts reasoned that Burns involved an NLRB order holding the successor employer bound by the substantive terms of the collective bargaining agreement with its predecessor (an order which the Supreme Court declined to enforce), whereas Howard Johnson, like Wiley, involved a section SOI suit to compel arbitration. The Supreme Court rejected the lower courts’ reasoning on this point. In its discussion of the issue, the Court said: Although this distinction was in fact suggested by the Court’s opinion in Burns, see [406 U.S.] at 285-286 [92 S.Ct. at 1581], we do not believe that the fundamental policies outlined in Burns can be so lightly disregarded. In Textile Workers v. Lincoln Mills, 353 U.S. 448 [77 S.Ct. 912, 1 L.Ed.2d 972] (1957), this Court held that § 301 of the Labor Management Relations Act authorized the federal courts to develop a federal common law regarding enforcement of collective-bargaining agreements. But Lincoln Mills did not envision any freewheeling inquiry into what the federal courts might find to be the most desirable rule, irrespective of congressional pronouncements. Rather, Lincoln Mills makes clear that this federal common law must be “fashion[ed] from the policy of our national labor laws.” Id., at 456 [77 S.Ct. at 917], MR. JUSTICE DOUGLAS described the process of analysis to be employed: “The Labor Management Relations Act expressly furnishes some substantive law. It points out what the parties may or may not do in certain sitúations. Other problems will lie in the penumbra of express statutory mandates. Some will lack express statutory sanction but will be solved by looking at the policy of the legislation and fashioning a remedy that will effectuate that policy.” Id., at 457 [77 S.Ct. at 918]. It would be plainly inconsistent with this view to say that the basic policies found controlling in an unfair labor practice context may be disregarded by the courts in a suit under § 301, and thus to permit the rights enjoyed by the new employer in a successorship context to depend upon the forum in which the union presses its claims. Clearly the reasoning of Burns must be taken into account here. 417 U.S. at 255-56, 94 S.Ct. at 2239-2240 (footnote omitted). Similarly, we think that it would be inconsistent with the congressional mandate to fashion the law under section 301 from the policy of our national labor laws to say that the policies found controlling in the unfair labor practice context described supra may be disregarded by the district court in the present suit under section 301 and thus to permit the rights and obligations of the parties to vary with the forum. The Court in Howard Johnson emphasized that [i]n our development of the federal common law under § 301, we must necessarily proceed cautiously, in the traditional case-by-case approach of the common law. Particularly in light of the difficulty of the successorship question, the myriad factual circumstances and legal contexts in which it can arise, and the absence of congressional guidance as to its resolution, emphasis on the facts of each case as it arises is especially appropriate. Id. at 256, 94 S.Ct. at 2240. The same can obviously be said for the single employer-alter ego questions presented by this case. At this preliminary stage of .the litigation, and for the purpose of deciding whether the plaintiffs have failed to state a claim, we see no reason why the substantive law to be applied by the district court should differ from that applied by the Board in the unfair labor practice context described supra. This brings us squarely to the question whether, as the district court held, a determination of the appropriateness of the bargaining unit by the district court would be an invasion of the exclusive province of the NLRB “not distinguishable from that condemned by the Supreme Court in the Peter Kiewit case.” 511 F.Supp. at 513. 5. The Relevance of Peter Kiewit. The defendants’ position is that the plaintiffs’ claims against Halmar must fail because the plaintiffs’ claim under the single employer theory would require the district court to make a determination of the relevant bargaining unit before the NLRB has done so, and such a premature determination is forbidden by the Supreme Court’s decision in Peter Kiewit. To hold Halmar (as a single employer with Farnsworth) to the 1977 collective bargaining agreement, say the defendants, it must be determined that Halmar’s employees belong to the relevant bargaining unit represented by the Unions. This in turn requires that a determination of the appropriateness of that bargaining unit be made, and according to defendants, Peter Kiewit does not allow the federal courts to make de novo bargaining unit determinations. The plaintiffs argue in response that Peter Kiewit does not forbid such unit determinations in the present section 301 action for breach of contract. We are in substantial agreement with the plaintiffs’ position. As described above, in Peter Kiewit the union filed an unfair labor practice charge before the NLRB against a union contractor and a non-union contractor, alleging that they were a single employer and that the contract entered into by the union contractor was binding on the non-union contractor. The NLRB found that the two contractors were separate employers, thereby obviating the need to inquire into the appropriateness of the bargaining unit, and dismissed the complaint. The Court of Appeals for the District of Columbia Circuit reversed, holding that the two contractors were a single employer. Rather than remanding for a determination by the Board on the appropriateness of the bargaining unit, the court went on to hold that the unit was appropriate and that the two contractors had committed an unfair labor practice by refusing to recognize the union as the bargaining representative of the non-union contractor’s employees or to extend to them the terms of the collective bargaining agreement. The Supreme Court affirmed the circuit court’s determination on the single employer issue but vacated its holding that the employees of the two companies constituted an appropriate bargaining unit. The Court held that the circuit court had invaded the statutory province of the NLRB under section 9(b) of the NLRA by proceeding to decide the unit question before the NLRB had passed upon the issue: Whether or not the Court of Appeals was correct in this reasoning, we think that for it to táke upon itself the initial determination of this issue was “incompatible with the orderly function of the process of judicial review.” NLRB v. Metropolitan Ins. Co., 380 U.S. 438, 444 [85 S.Ct. 1061, 1064, 13 L.Ed.2d 951] (1965). Since the selection of an appropriate bargaining unit lies largely within the discretion of the Board, whose decision, “if not final, is rarely to be disturbed,” Packard Motor Co. v. NLRB, 330 U.S. 485, 491 [67 S.Ct. 789, 793, 91 L.Ed. 1040] (1947), we think the function of the Court of Appeals ended when the Board’s error on the “employer” issue was “laid bare.” FPC v. Idaho Power Co., 344 U.S. 17, 20 [73 S.Ct. 85, 86, 97 L.Ed. 15] (1952). As this Court stated in NLRB v. Food Store Employees, 417 U.S. 1, 9 [94 S.Ct. 2074, 2079, 40 L.Ed.2d 612] (1974): “It is a guiding principle of administrative law, long recognized by this Court, that ‘an administrative determination in which is imbedded a legal question open to judicial review does not impliedly foreclose the administrative agency, after its error has been corrected, from enforcing the legislative policy committed to its charge.’ FCC v. Pottsville Broadcasting Co., 309 U.S. 134, 145 [60 S.Ct. 437, 442, 84 L.Ed. 656] (1940).” In foreclosing the Board from the opportunity to determine the appropriate bargaining unit under § 9, the Court of Appeals did not give “due observance [to] the distribution of authority made by Congress as between its power to regulate commerce and the reviewing power which it has conferred upon the courts under Article III of the Constitution.” FCC v. Pottsville Broadcasting Co., 309 U.S. 134, 141 [60 S.Ct. 437, 440, 84 L.Ed. 656] (1940). Peter Kiewit, 425 U.S. at 805-06, 96 S.Ct. at 1844-1845. We do not think that the second sentence in the portion of the opinion quoted above — a sentence which is often quoted out of context — stands for the proposition for which it and Peter Kiewit are cited by the defendants — that the Board has exclusive jurisdiction to decide appropriateness of the bargaining unit issues. We think instead that the Court in Peter Kiewit was applying a time-honored principle relating to appellate review of an agency determination. When an agency, in order to grant relief in the case before it, must as a matter of statute find that both factual or legal conclusion A (e.g., single employer status) and factual or legal conclusion B (e.g., appropriateness of the bargaining unit) have been established, but concludes that A has not been established and therefore declines to consider whether B has been established, a reviewing court that reverses the conclusion that A has not been established must remand to the agency to permit it to consider in the first instance whether B has been established. Section 9(b), which is the source of the Board’s responsibility in an unfair labor practice context to make a determination of the appropriateness of the bargaining unit in a single employer case such as Peter Kiewit, and which is set forth in the Supreme Court’s opinion in Peter Kiewit, directs the Board to “decide in each case whether, in order to assure to employees the fullest freedom in exercising the rights guaranteed by [the NLRA], the unit appropriate for the purposes of collective bargaining shall be the employer unit, craft unit, plant unit or subdivision thereof.... ” 29 U.S.C. § 159(b) (emphasis added). Clearly section 9(b) refers only to cases pending before the Board under the NLRA. Neither section 9(b) nor the Supreme Court’s decision in Peter Kiewit stands for the proposition that a federal court with jurisdiction under section 301 of the LMRA to decide cases alleging a breach of a collective bargaining agreement by related employers does not have jurisdiction to determine whether a bargaining unit comprising the employees of such employers is appropriate where such a determination is necessary to a resolution of the breach of contract issue that is consistent with national labor policy. We note that in the present case there is no indication that either party has been before the Board seeking a certification or clarification of the relevant bargaining unit, nor to our knowledge is any such proceeding presently pending. Were such a circumstance present, our view of the proper role of the federal district court in that case might be very different. We do not deny that deference to the expertise of the Board in unit determinations should be encouraged whenever possible, and upon the initiation of clarification proceedings or the filing of an unfair labor practice by one of the parties to this action, depending upon how far these proceedings had progressed, the wisest course for the district court might well be to stay the action pending the Board’s resolution of the unit issue. Nor is this a case in which a unit determination has been made by the Board and a disgruntled party seeks to circumvent it through a de novo determination by a federal court under the guise of a section 301 action. In that case, as well, the outcome might be very different. We have before us a narrow set of circumstances in which neither side has sought to invoke