Hit by Pitch Rule

[SeaDude]

I know some leagues in Michigan have adopted a "Hit by Pitch" rule that states that a pitcher is to be removed if they hit 2 batters in one inning or 3 batters in a game. I would like to know if that is a Statewide rule, a NFHS or ASA rule, or even an NCAA rule? Or is it just simply a league rule. I have searched but can't seem to find it anywhere.

Thanks.