Try using Zones (add a Multi-Zone grid to the board). Within the Zone, define an Irregular Grid. Pieces will then only be able to be dragged to the locations you define on that Zone. It might work to simply define no locations (haven't tried) or you can just define one location at the edge of the Zone, and pieces will snap there when players try to drag into the forbidden Zone.
rk [Non-text portions of this message have been removed]
