Mich. Comp. Laws § 38.428
Any other provisions of this act to the contrary notwithstanding, in the event of the consolidation of functions or departments of another governmental unit with a county department now, or which may hereafter be established, the civil service commission of the county shall make equitable rules and regulations governing the employment, status and all other terms and conditions of employment of employees of the other governmental unit in order to effect an orderly transfer of the employees to the county service and to provide, as near as may be practicable, the same conditions of employment as other county employees in like categories. The rules shall provide that the initial county status and county classification of the employees shall be based upon the status, duties and responsibilities exercised immediately preceding the date of consolidation. Any subsequent changes in status or classification shall be made in accordance with the rules of the county civil service commission.
MCL 38.428