I'm pretty sure that technically there is not supposed to be any communication between judges, but they sit pretty close to each other, so it would be difficult or impossible to police it.
I thought the judges are pretty much placed on opposite sides of octagon for different points of view. Never really bothered to find out where they exactly sit though so I cold be wrong about that.
"When I land that left hook, the fight will be over." -Paul Daley (He called it!)