If two districts, one of which is a community college district, have been included in one contract between the Board of Administration of the Public Employees’ Retirement System and the governing board of the districts, as provided in paragraph (7) of subdivision (b) of Section 24810, and thereafter members of the governing board of the community college district are precluded by law from serving as members of the governing body of the other district, the contract shall be deemed a separate contract as to each district. The Board of Administration of the Public Employees’ Retirement System shall determine the accumulated contributions held for or as having been made by each district and its employees, and shall credit the contributions to the respective contracts. Benefits based on all service of an employee to the districts prior to the date upon which employees’ elections to serve the respective districts are effective shall be a liability of the contract of the district employing the person on the effective date. A person retired prior to the effective date shall, for all purposes of this section, be deemed an employee of the district other than the community college district.