Delete objects in backbone-relational

let's say I have two HasMany relationships:

Playlist: HasMany Clips

and

ClipsMegaCollection: HasMany Clips

The idea is to have a sorted list of Playlists and keep a ClipsMegaCollection synchronized as the planar list of clips reflecting all the playlists.

Is this possible with backbone-relational, or can anyone think of a way of doing this in backbone?

I can have ClipsMegaCollection.comparator return a key depending on Playlist order and Clip order within the playlist, so keeping things sorted should be OK.

The problem is that I need to keep things synchronized when clips are added or removed from playlists, or moved around