It sounds like this is something that can be accomplished with custom fields and some expression language finnagling?
Maybe someone good with expressions could help you out there.
I had a similar question a while back I think, but it was more related to shows than movies. I think the principle would be the same. I did some similar stuff before using a "Franchise" tag (don't remember if its custom or already present) and arranged stuff like Star Trek, Star Wars, and Mobile Suit Gundam under their own single top-level selections.
I've since lost that setup for various reasons, but this should be very possible for your to accomplish with expressions and tag fields of some sort if you look into it more.