[DaveBlake]

Thanks for the advice. It never occurred to me to use genre tag. So, if I tag something as "Rock / Stereo" does that create two separate genres... one "Rock" and one "Stereo" or is it a single genre labeled "Rock / Stereo?"

RELEASETYPE tag sounds like a great option. Unfortunately, I'm still on v16. Ive been planning to give v17 a try. Hoping I might find some time to do it today. Can I use most any tagging app to add RELEASETYPE tag?

Thanks!

I abuse the genre tag in all kinds of ways

In FLAC (Vorbis) and ID3 v2.4 tag formats GENRE is multivalue, while in v2.3 only single value. Either way Kodi will parse a string using the standard item separator (slash-space-slash by default) into separate genres. So "Rock / Stereo" will create two separate genres, one "Rock" and one "Stereo".

RELEASETYPE is an appropraite use if you give v17 a go.

Yes most tagging software will let you add new tags, I use Mp3tag a lot. But take care with naming any tags you add: Kodi is looking for the RELEASETYPE tag to be named as Picard does in the various music file formats. That is:
TXXX:MusicBrainz Album Type (Id3 v2.4),
RELEASETYPE (Vorbis/Xiphe/FLAC),
MUSICBRAINZ_ALBUMTYPE (APE),
MusicBrainz/Album Type (ASF),
----:com.apple.iTunes:MusicBrainz Album Type (mp4/iTunes)

Crazy lack of consistency, but made sense for Kodi to adapt to what Picard was outputting.

And finally, there is always folder path, save messing with tags at all