Some efficient ways of leveling 20 characters at once (Horde side)?

[dustofoblivion]

get 5 to 60 and use them to help boost the others. preferably 1 tank 3 aoe 1 healer.

I thought about doing that, but I had some concerns that the strategy of pulling the entire dungeon and then leaving the party/instance might be considered abuse and be bannable. Is it the case?