Moving mc's inside another mc?

I’m working on a thing where I use drag n drop. So far so good, but when the mc’s is dropped on the drop target (which is also a mc) I want them to get inside that mc in some way. This is because I need to be able to move the droptarget_mc and the dropped mc’s together with it! If I can get them all in the same mc the problem is solved…

Any ideas?