Album security

Dear All

I am trying to create an album which is

(a) visible to the public (no problem) AND
(b) to which registered users can MOVE their own albums (or delete it) BUT
(c) in which only the users can CREATE a new album.

At the moment, if I give permission to create a SUB-ALBUM, I also give permission to create a NEW album. I do not want them to be able to create new albums.

In short, I want to set up an album which does not allow the creation of a new album but which will accept that an already-created album be moved into it.

Thanks for any help.
Andrew