RTF is a global modification that replaces all towns in the game.

in the original Heroes, there was a feature with unique schools of magic (except for dwarves and elves). I would like to keep this feature; here's my suggestion:
fire and air - Haven
fire and water - Conflux
fire and earth - Fortress
air and earth - Stronghold
air and water - Sanctuary
water and earth - Academy + Necropolis