The County Employees Retirement Law authorizes implementation of various COLAs to the pension benefit. Prepare the Request for Joinder of Employee Pension Benefit Plan and Order.(Family Law) (FL-372). 3. Eligibility and Entry Date: Most employees are eligible to participate in the 403(b) and 457(b) Plans immediately upon employment; however, private. The County Employees Retirement Act of 1937 provided for retirement systems for California counties. Plan Description The District participates in the Contra Costa County Employees' Retirement. We offer a dental plan for full time employees and 2 dental plans for part time faculty, all through Delta Dental. County employees retirement.