Any Employer (including an Association of Employers) who is or becomes a party to a Collective Bargaining Agreement and who, with the acquiescence of the Trustees, agrees to be bound by the Trust Agreement and this Plan and is accepted for participation in the Plan by the Trustees, subject to such rules as the Trustees may in their discretion adopt. The Union, the Health Fund and the Pension Fund shall be deemed to be Employers of those persons employed and proposed by such organizations and accepted by the Trustees.