Feature Request: "Remove fields except" and wildcards

I’m working with MusicBrainz a lot, so when »cleaning up« files using an action »Remove Fields except …« I’d very much like to leave groups of fields intact and not remove them, i.e. all fields starting with »MUSICBRAINZ«.

So it would be just great if the »Remove Fields except« action could handle things like:

Remove fields except MUSICBRAINZ*
(to keep all existing MusicBrainz tags)

or

Remove fields except MUSICBRAINZ?ALBUM*
(to keep MusicBrainz Album Information regardless of file type [stored as »MUSICBRAINZ_ALBUMARTIST« in Ogg Vorbis, as »MUSICBRAINZ ALBUM ARTIST« in MPEG ID3])


Does anyone have a better wording for »Feature Request«? I always find it a little offensive to »request« something from someone who already gives away a great piece of software without »requesting« payment for it … and I guess we all greatly appreciate the work Florian puts into Mp3tag.