That's Kinda not Smart to do an instance with 3 tanks, who can't really DPS that well. The reason this is happening to you cuz a lot of fight are designed for 1 tank a heal and two DPS. You guys are in for a lot of heart ache trying to roll like that cuz some bosses are on timers and rape if you don't DPS down certain things fast. Plus tanks are rare by rolling an instance with 3 tanks you denied like 6 people that are queued a chance to do the instance with your friends as tanks. You really don't meet the requirement cuz you don't have a real healer like white mage or conj a anch aint going to cut it. Tanks get into dungeon when qued like instantly cuz they are so rare. Srun the dungeons separately then talk about it after its over and share the experiences :P