Folders for media files

It would be great to have folders for media files. For instance, I want to upload rehearsal audio tracks in different keys, but the current design just stacks all the files in one long list.
It would be better if there were an option to create folders or subfolders—for example:
* "Praise - A": Contains all rehearsal tracks in the key of A
* "Praise - G": Contains all rehearsal tracks in the key of G
* "Praise - F": Contains all rehearsal tracks in the key of F...

...and this way, things would be much more organized for the musicians.