1st you need 2 people in the group.
get close to any lair, make 1 group member stand around 35-40m from the lair without attacking,
other member run up and attack the lair for around 15-20sec, dont blow it up. *the longer you hit the lair* the more mobs come out.
after that 15-20 sec attacking the lair, run away untill u loose agro. stand next to ur buddy watching the spawn rate on that lair go crazy, lol enjoy
(Relly easy to kill everything there if you have a Officer and a Tank doing this)
Have fun.
Dont know if this is posted or not. either way, Enjoy