...Yeah, Ive done that dungeon as a PLD and BLM... I explicitly tell people, "Stack on her butt. Do not move unless its to dodge a ground effect, and if you do move, get back into position when it is safe."
This way the mobs are mostly within Flash and Provoke range of the tank, and makes aoe'ing them down easier, since the small adds hit for nothing, while the bigger adds, Marshall and the 2 big, think they are Soldiers, do need to be tanked.