I have a similar inquiry. Probably would lead to the same thing though. I built a vault door for a bank (it's old school), but it also has a small glass door in the inside of it that opens to adjust the mechanics. Was wondering if it's possible to be able to open the glass door on the back, even though it's nested under the same component as the vault door too. So far I've tried assigning attributes to parts of the vault door, so if you click a piece of the vault door, it rotates the whole thing, but haven't had any luck with that. But if I assign the attribute the whole component, I can't get the glass door to open. 
Anyone have any clues? I'm very much a noob at this!