I don't know anything about that mod, but if it separates the regions to different folders in the "music" datafiles folder, I'd venture to guess that they can be added that way, the same way you can add music to the "explore" folder.
Well it's not quite that way.
It has you rename your Explore and Battle folders to 'Explore disabled' and 'Battle disabled'.
Then you extract the files which has about 5-10 tracks for each region(and even different dungeons) with a battle track for each region as well.
Thing is they are not in their own folder, they just sit in the main music folder all scattered.
When I get off work tonight I'll do some fiddling with it to see how it operates exactly.