Just trioed as 61DRG/BLM 75NIN 61BRD. (i am the DRG) I died due to a very high ammount of En-fire damage that COULD NOT be dispelled. (and massive spamming of the Blood drain TP move) BRD had to soul voice paeon4/3 to survive this fight. (75NIN got to about 100HP at one point.)
NIN tank is a must on this or alot of healing power.
Also another thing, these guys can be slept by BRD ofcourse. Sleep would last about 1 minute on the guardians at which they have to be reslept. not too hard of a battle if you're prepared.