as a matter a fact, I do have an idea. I saw it in an academy. I forgot which one, isn't important. What they did, was that everyone starts at the lowest dorm, and by gaining exp you can rank up in level in that dorm. Each dorm would have 5 levels, and with each level, the amount of experience required to level up would increase a little. And when you leveled up, or ranked up, your exp is reset to 0 again, or something.Kinda like this:
Gusto lv 1: standard
Gusto lv 2: 10 exp
Gusto lv 3: 12 exp
Gusto lv 4: 14 exp
Gusto lv 5: 16 exp
Ice Barrier lv 1: 18 exp
Ice Barrier lv 2 : 20 exp
etc...