I had GS/NP as the protected rivalry for Watermelon Bowl purposes, but then changed it. A lot would depend on the dividing line. If MtV played in the smaller division, then that's exactly what I would suggest.
Large - JAS, BV, WAS, VL, GS, PT, HH
Small - MTV, PC, SR, FP, SS, NP, TC
That would produce the ability to have JAS/SR, GS/NP, and HH/SS as neighbor school-district rivalries. The other 8 could be matched up on a rotating basis. Hopefully a competitive slate of games would result in some new rivalries and larger ticket gates for schools that traditionally haven't had success.