In Collection

In light of the discussion elsewhere on this Forum, I have a slightly different request concerning In Collection status. As far as I can tell, currently In Collection applies only at the album level. But in this day and age of iTunes, emusic, and other download-by-track services, it is often not the whole album that is not in the collection, but specific tracks from an album. I would like to be able to indicate which tracks I have and which I do not. Could this be added to the track properties (and displayed as default)?