Notwithstanding the provisions of Kan. Stat. Ann. §§ 74-4913 to the contrary, any employee of a county who became a member of the Kansas public employees retirement system on the county’s entry date of January 1, 1967, who was first employed by said county on June 1, 1961, and who had been employed periodically by several other participating employers during the period of September, 1933 until May of 1959, shall upon retirement be granted prior service credit for all service with a participating employer prior to the county’s entry date whether such service was continuous or not.