Reign of Kings PvP in areas, kill at night

There is a plugin where you can disable PVP in areas, but I want to build an arena where players can only fight in there, everywhere else PVP is disabled. Also night KoS is enabled everywhere, so the 2 would kind of need work together!

Would this even be possible?

Extra:
You can always die if you are king

Idk if something like this is possible, just and idea I had.