here is how I see the groupings, based on what I have seen & heard
1-3 BD, SCV, Bluecoats
4-6 Crown, Cavaliers, Boston
7-11 Mandarins, Cadets, Blue Stars, Crossmen, Blue Knights
12- 14 Phantom, Spirit, Academy
15-18 Colts. Scouts, Troopers, Music City
19-20 Pacific Crest, Genesis
21-22 Cascades, Surf