Multiple Users Editing Shared Collections

When working with a team, it would be nice to be able to share a collection with a team member or client, which we can already do. HOWEVER, it would be much more useful if the person with whom the collection is shared can EDIT that collection, or at least add to it. This way if I find a song, I can add it to a shared collection that my whole team can access. This would make the selection process much easier and more client-friendly as well.