[Geoff Bacon]

If you can't get what you want, an alternative approach is to have duplicates but put each edition into it's own collection; this would allow you to filter on the collection name (it also allows you to select/delete all songs so that the file can be reimported with an updated .csv file)

Or use one of the other fields to specify the edition e.g. Sources.
Modify the display of the song name so that it also shows this field (filtering would then be by eyeball - unless you combine the two techniques)

Geoff