The best way to beat them is to not que against them. Don't give them anything to farm
or any more reason to brag. I'd rather wait a few hours for a more balanced match than have the que poping every 5-15 minutes against constantly stacked teams.
If you see a team or people you recognize that always group together, let your team know. Say it out loud in the PvP Chat to let the other teams know too. No point in feeding their egos. Let them starve in a dead PvP Que instead.