[samibe]

While the song versioning would be amazing, I think I could almost replicate it with a few more custom groups. I've already started using the albums group this way for some things. 
Currently, I use the albums field to list what book the song is from, what recorded album it was released on, what movie or show it's from (for soundtracks and scores), what suite or opus it's from (for classical works), or what the tune name is (for hymns and folk songs).
If I had an extra custom group, I could name it something like "unique songs" or "versions" and group different versions of the same song under the same song entry (even if it might be titled differently). This would allow me to simplify the 'albums' information and find all of the versions of different songs I have.