Whenever in this part an election is given to contracting agencies to subject themselves and their employees to provisions of this part otherwise not applicable to contracting agencies and their employees, a contracting agency may exercise the right of election independently with respect to its employees included in the insurance system established under Title II of the Social Security Act and with respect to its employees not so included and with respect to those employees who are local police officers, local firefighters, county peace officers, local safety members other than local police officers or local firefighters or county peace officers, and local miscellaneous members.