This is an easy fix. When my guild is double towering we just say the name of the tower then flag so which group is being talked to. It is annoying when you do certain events and it changes your chat during the event then you have to reset your tag after words.
It would be nice if there was a third chat box for admin notifications like upload approval,event notice,ect. then use it for the gc in certain events. I don't know how many times I've missed events or nearly missed events becuase the event notice was buried in the middle of a dozen gc spam messages. I think when an event pops up it should have its own chime or seperate box.