deppends on your town if they have rules in place about it or not i do know that they must be in separate locked rooms with each other not having access to each others
I would keep each grow in its own room with no adjoining doors just the ability to make a reasonable case if you go to court.
Traverse City has 7 or 8 in one large house downtown
7-8 in one place? damn i live in traverse too and i havent heard of this, but i also have been wondering about ho wmany caregivers can be in one house lol