Mich. Comp. Laws § 205.744: Intervention or impleading.

Sec. 44.

Except for petitions filed under chapter 6, the tax tribunal may permit the intervention or impleading of any governmental unit which receives tax funds from the petitioner who is making the appeal.

If a petition is filed under chapter 6, the tribunal may permit the intervention or impleading of a state or local governmental unit or officer thereof or of any person or other entity upon a showing of a material monetary interest in the decision of the tribunal which is not likely to be adequately presented by the parties to the proceeding.