Everyone is pretty correct here. I have had some similiar experiences.
The main thing I did that made it be less of an issue as far as "territory" - which is mainly sleeping dens, is that I moved some of the stuff around on the bottom of my tank so they all would have to find new sleeping quarters since they sleep in the sand generally. One of my Hawaiian's sleeps inside a rock that has a cave just big enough for him - facing straight up, its pretty funny actually.
Other than that, the only issue I have had is my Mystery chasing around my female splendid leopard till she died - which it could have been that she was already stressed out and he just made sure she went over the edge, who knows.
I'll be adding more later from Halichoeres, to Cirrhilabrus and Marco's.