Pitching rules for players playing both AAU & Town League

The League I'm involved in has a new dilemma, and I was wondering if anyone has suggestions.

A new 12 yr.old AAU team is starting up in our area and some of our players will probably be playing both AAU and Town League our dilemma is what about pitching rules we currently use the standard 6 innings aweek with proper rest. Do we limit these players pitching innings seeing they might pitch for the AAU team plus in our league (they might not pitch for the AAU team who knows)or do we put this squarely on the parents to let the coachs know if the child is pitching for AAU and how much?

Thanks Don C