In MMA, teammates fighting each other doesn't happen. It's a code of bond. Unless it is a title fight, they don't see a reason to step inside the cage. If you want to see them, go to their respective gyms and watch them train against one another.
Alistair Overeem and Andrei Arlovski also train at the same Albuquerque gym. Arlovski has been a long time staple of the gym while Overeem started training at the gym in 2014. Now they are battling in the main event of Sunday's UFC Fight Night 87. The top-ranked heavyweights have different versions of how the fight was made.