From a tactical standpoint, I've seen that used as a battle strategy. 3 healers, 1 tank (usually a WAR for the dps), and 4 dps

Tank/melee DPS scouts/marks targets ahead of the party, either the tank stuns, or the melee opens with a stun, then all engage that single target and neutralize. If the tank/melee is engaged first, healers set to work overhealing any damage done as they fall back to the healer line, while ranged begins to pick them off. If the healer is somehow targeted, the healers focus on each other as the melee flanks & stuns, and all DPS neutralize the attacker.

There's of course, variations of this strat, but it effectively covers both offense and defense in nearly any situation.