Using 'grouping' tag in music library

Hi, is there a hack or an addon that would allow me to take advantage of the 'grouping' tag? My music collection is organized around this tag.

Itunes, Mediamonkey and Banshee use it, but not others. It is an MP3 tag that's written into the file, though. I use this for subgenres, and for other classifications (like 'ballad', 'live' etc).

I guess I could try to find a way to move these values into the 'comment' field, which xbmc will use for smart playlists. I have tried creating an xml smart playlist that uses 'grouping' but it gets ignored. Maybe there's some other hack I can use to make xbmc recognize this field, or an add-on?

In general, I would like to try and enhance the music player for the sake of organization, so if you could recommend the best tools, it would be appreciated

More information on the 'grouping' tag, from an iTunes forum:

"iTunes uses the TPE2 frame tag for grouping. This is also known as the 'Band/Orchestra/Accompaniment' frame"

I'm assuming xbmc uses ID3, where the field is known as "Band/Orchestra/Accompaniment". So if there's a way to enable more standard ID3 tag fields, for the purpose of creating smart playlists, this would be very helpful.

Grouping is the TIT1 frame in ID32.3 and 2.4 and is what iTunes uses for styles. ID3 specs it as "Content group description". XBMC Eden does not recognize this yet, but I'm holding out for Frodo to make any decisions. I have no Apple devices anymore in the house, but have been tagging with allmusic Genres and Styles. Ultimately I would like to see a hierarchy of Genres with lists of Styles beneath. As of right now, I'm tagging Genres and Styles in one null-delimited tag and I understand Frodo will be able to parse nulls to return a list of Styles and Genres.