Mich. Comp. Laws § 600.401

Sec. 401. (1) Within each judicial circuit, subject to approval by the supreme court and to the limitations contained in sections 410, 841, and 8304, a plan of concurrent jurisdiction shall be adopted by a majority vote of all of the judges of the trial courts in the plan unless a majority of all of the judges of the trial courts in that judicial circuit vote not to have a plan of concurrent jurisdiction. If a majority of all of the judges of the trial courts in a judicial circuit vote not to have a plan of concurrent jurisdiction, the chief judge of the circuit court of that judicial circuit shall report the results of that vote to the state court administrator. (2) A plan of concurrent jurisdiction under this section may provide for 1 or more of the following: (a) The circuit court and 1 or more circuit judges may exercise the power and jurisdiction of the probate court. (b) The circuit court and 1 or more circuit judges may exercise the power and jurisdiction of the district court. (c) The probate court and 1 or more probate judges may exercise the power and jurisdiction of the circuit court. (d) The probate court and 1 or more probate judges may exercise the power and jurisdiction of the district court. (e) The district court and 1 or more district judges may exercise the power and jurisdiction of the circuit court. (f) The district court and 1 or more district judges may exercise the power and jurisdiction of the probate court. (g) If there are multiple district court districts within the judicial circuit, 1 or more district judges may exercise the power and jurisdiction of judge of another district court district within the judicial circuit. (3) A plan of concurrent jurisdiction under this section shall provide for the transfer or assignment of cases between the trial courts affected by the plan and to individual judges of those courts as necessary to implement the plan and to fairly distribute the workload among those judges. (4) A plan of concurrent jurisdiction under this section may include agreements as to other matters involving the operation of the trial courts participating in the plan, as approved by the supreme court. (5) A plan of concurrent jurisdiction becomes effective upon the approval of the plan by the supreme court. (6) This section does not apply to the counties of Genesee, Ingham, Kent, Macomb, Oakland, Washtenaw, and Wayne, which have district court districts of the third class.