AS2: drop target

I’ve been making this drag and drop game where you have 11 cards (the drag items) and 4 drop spots (Any of the 11 cards can go onto the 4 drops) - I need to make it so that once any of the 11 cards has hit the drop spot then that drop spot becomes deactivated and if you try and pull any other cards onto it, it won’t hit.

I’ve tried drop1_mc.enabled = false and removeMovieClip(drop1_mc);