no no no. hellfire. not rain of fire. your warlock should have hellfire, which is an AoE spell that comes from the warlock. it must be channeled, and he must not move. its like arcane explosion or holy nova. he's the center of the AoE. if you have a gnome, the animation looks like he's farting out fire. anyway....

the AoE spells will take care of your totems quick. or you can have a toten killing macro stick to you warlock. i say warlock because your priest has better things to do than be on totem duty.

/target "totem_name"
/target "totem_name"
/target "all other totem names"
/shoot

what i'd do is have your team just stand in one spot and wait.
have the pally do his thing and run around. when you feel that you've gathered enough mobs, run back but only within 25-30 yards of your team. use a corner to take advantage of LOS so the casters come in close.
consecrate, blah blah blah.
press /follow on all your alts.
once they are next to you, have them go at it. =]