drag n drop - no overlap?

[o rly?]

hey, i have been doing alot of searching but am having trouble finding what im looking for.

what i have is a stage full of drag and drop movie clips, im trying to get these clips to not overlap when being dragged around the screen, maybe by setting some type of "feild" around each movie clip, or by "reserving" the space each movie clip is in so other cannot be dragged on top/over.

any help on the name of the technique i should search for or helpful tuts on this..thanks!