Tas I agree with you completely on the need to stop it..
The best PvP/PvE groups I have ever been part of were strictly organized and very focused..The person who is in charge of the group should be more in reserve from the actual combat and taking on a roll of oversite, focusing the group on single targets and keeping the group tightly formed..Vent chatter needs to kept to an absolute minimum when its game time and the only ones talking should be the group lead calling targets and revives.If we stay tight there will be no ganks..When the group lead moves he calls it and everyone moves in unison..Mounts and dismounts and engages and disengages as a unit.
Discipline and communication..The biggest thing to remember is its okay to fail over and over again as long as you stick to the process and learn a little bit more each time..This game the advantage is definitely with ranged combat and let them come to you rather than us to them..Once your commited to hand to hand melee because of the game mechanics it becomes harder to keep everyone focused, but its not impossible..