Mich. Comp. Laws § 3.888: Supplementary jurisdictions.

Sec. 8.

(1) Because it is probable that the pattern and detail of the agreement for mutual aid among 2 or more participating jurisdictions may differ from that among the participating jurisdictions that are party to this memorandum of agreement, this agreement contains elements of a broad base common to all participating jurisdictions, and nothing in this agreement precludes any participating jurisdiction from entering into supplementary agreements with another jurisdiction or affects any other agreements already in force among participating jurisdictions.

(2) Supplementary agreements may include, but are not limited to, provisions for evacuation and reception of injured and other persons and the exchange of medical, fire, public utility, reconnaissance, welfare, transportation, and communications personnel, equipment, and supplies.