Body pull the Warmasters and start running out. A rogue with sprint works best. A tank should shoot the primary target and DPS should begin on this one. The body-puller should run past the East + West towers, resetting the other mob(s) that are aggro'd to them. Obviously, nobody should attack the mob(s) that will be reset.
The primary target should be Stonehearth, Icewing, and Dun Baldar WM's if they are up. Don't attack a Frostwolf Warmaster when there are other Warmasters to kill, or there's less than a minute left on their Frostwolf Tower. They will despawn anyway.
You would think this shit would be common sense by this point, but you would be surprised by Alliance logic.
Also for the Horde: You can win every game in under 25 minutes if you just rush Aid Station through back door as 40 and skip every objective. I'm sure the above strategy works for pulling the Alliance Warmasters too, you just have to kill more of them.