I did this one with 2 other friends of mine and we beat the record all three times.
Setup was:
Pld/War
Pld/War
Nin/Blu(me) wanted to try an out of the box approach.
What we did was of course buff up and I chose to eat a jack-o-lantern. The reason, was for the inc EVA and Arcana killer. After buffing we went up to the entrance of the open room and selected one of the the three monsters to solo. One of the paladins then used the def job ability and pulled all 3. We each grabbed our mobs and went to seperate corners of the arena. That was so the aoes of the weapons would stack. I was able to land Blu spells pretty easily I also used the slow,blind, and paralyze jutsus. This made the battle too easy. After we finishedoff our mob we would go and take out the one with the lowest hp.
NOTE: Some important things you must do, is make macros for each weapon type. Also if you want to save tp, and use crossbows do not switch to a piercing weapon. Lastly, find out what type of classes have special damage types. E.g épée, a sword class, does piercing damage.