(1) The State of Oklahoma, any county, city or town, or any instrumentality thereof whose employees or a class of whose employees are members of any other retirement or pension plan authorized by a statute of the State of Oklahoma may, by resolution adopted by the official board, body, or officer or officers authorized to apply for application, request the board to submit a proposal for consolidation of such other system with the Oklahoma Public Employees Retirement System, including an estimate of the contribution rate necessary to comply with the actuarial standard of this System. Such proposal shall provide that: (a) the operation of such other pension system shall be discontinued; (b) the existing retirants or annuitants of such other system shall continue to be paid by the Oklahoma Public Employees Retirement System on the basis of the benefits schedule applicable to such other system at the date of proposed consolidation; (c) all cash and securities to the credit of such other system shall be transferred to the Oklahoma Public Employees Retirement System; (d) funds of such other system which represent accumulated contributions, if any, of members shall be credited to the employees accumulated contribution reserve of each employee. The balance of the funds so transferred to the Oklahoma Public Employees Retirement System shall be offset against the liability on account of existing retirants, annuitants, and active members; (e) the resulting liability so determined shall be the basis for a rate of contribution of such employer; (f) such consolidation shall take effect only on the anniversary of the entry date.