Library: Folders for Collections

I have not only "normal " Collection for real use:
In addition to them, I have meanwhile already also some "support Collections", that serve only as kind of advanced Tag. I don't need to see them mixed with the normal Collections in the Library, the list there becomes long and messy.

Therefore, I would like to have folders in the Library in which I could put the unimportant Collections, to have them out of view

Btw.: In addition to that, also a sorting function would be welcome for the Library.