Hopefully, collections like keywords and binders will have infinite levels of tree structure, with ICONS

I need without changing the structure of the binder, will step into a different collection of different document, but now collect cannot practice tree structure, such as a character, he is Chinese, cantonese, I can be assigned to China and guangdong two collected at the same time, but the two collection is the structure of the supervisor, and now the collection is parallel, guangdong below not in China, it makes me very upset.

Collections are lists of items, taken out of the hierarchy individually. I do not understand how they would have their own hierarchy—or at least in a way that would make sense with the rest of the software. Well I can say that will never happen, it’s not what the feature is meant to do.

So a better question is: what is it you are trying to accomplish? Would filtering the outliner view be a way of getting to that point?