a collective bargaining agreement that provides for contributions to and accruals under the composite plan in lieu of accruals under the legacy plan. (4) Collective bargaining agreement As used in this subpart, the term collective bargaining agreement includes any agreement under which an employer has an obligation to contribute to a plan. (5) Other terms Any term used in this subpart which is not defined in this part and which is also used in section 432 shall have the same meaning provided such term in such section. (b) Restrictions on acceptance by composite plan of agreements and contributions (1) In general The plan sponsor of a composite plan shall not accept or recognize a collective bargaining agreement (or any modification to such agreement), and no contributions may be accepted and no benefits may be accrued or otherwise earned under the agreement— (A) in any case in which the plan actuary of any defined benefit plan that would be treated as a legacy plan with respect to such composite plan has certified under section 432(b)(3) that such defined benefit plan is or will be in critical status for the plan year in which such agreement would take effect or for any of the succeeding 5 plan years, and (B) unless the agreement requires each employer who is a party to such agreement, including employers whose employees are not participants in the legacy plan, to provide contributions to the legacy plan with respect to such composite plan in a manner that satisfies the transition contribution requirements of subsection (d). (2) Notice Not later than 30 days after a determination by a plan sponsor of a composite plan that an agreement fails to satisfy the requirements described in paragraph (1), the plan sponsor shall provide notification of such failure and the reasons for such determination to— (A) the parties to the agreement, (B) active participants of the composite plan who have ceased to accrue or otherwise earn benefits with respect to service with an employer pursuant to paragraph (1), and (C) the