Heavily depends on what the rules are, such as how far apart are you standing? (this might be relevant for how much time you might have to hit certain buffs), what you both sub, and how well geared each player is. I recall going as SAM/WAR and fighting against a DRG/WHM a while back, and had zero problems taking the DRG out, a well placed Gekko goes a long way. Hard to say now though, with new gear and different subjob choices.