Panties ---> Bunch.
I tease because I care.

Seriously though, I read you going on about totem strategies. But when I was 5 boxing mages + priest, I had no strategy against any single targets. They only lived for a second or two anyway. DPS + Heal and AoE as many targets as possible really. None of this "ice shield against melee" or "mana shield against warriors and rogues but not hunters". It was pretty much target --> gibbed target --> gibbed target --> gibbed. Rinse and repeat.

Ok, sure - rank 1 Blizzard against rogues, etc. But by and large that was just fluff that got in the way of PvP. 5 vs 1 is so lopsided that you don't counter them. You just destroy them and heal right through it.