This works:
Example Party:
Tank - level 50
Heals - level 40-70
DPS: level 11
DPS: level 23
DPS: level 17
Whoever is the highest level (it could be more than one person) have them IMMEDIATELY run out of the group and down the hall a little so they don’t reset the fight–but just can’t get sucked back in with the Spirit Totem spell.
Then just have the others kill the boss.
My group the tank (level 62) and me (heals level 51) ran away and just let the three DPS (between levels 10-25) kill them.
Worked beautifully.