Overlapping irregular grids, and restricting cards to them


I would like to restrict the movement of certain cards/pieces to certain grids. So, the pieces in one deck can be dragged to one grid pattern, and the pieces of another deck can only be dragged to a different grid. And… the grids can overlap too: the pieces in one grid should always be ‘on top’ of the other pieces, no matter what.

Possibly this is doable with multiple (overlapping) boards with overlapping grids? But I need to make sure the pieces in the corresponding decks only snap to the appropriate grids.

Any suggestions as to the best way to do this?