Clique Creek ~Sensei, Watashi mo Tatakaimasu!~

Five academies form an academic town, and "School Integration Bureau" is set to cooperate. One former vice presidents gets worried about the education quality drop, so he occupies facility for his students only. That causes struggle between different faculties which continues every day. It's special jurisdiction, so police can not intervene. Main character is sent to this academy to mend things.

[From vndbreview]