I;m assuimng this is the bad guys in their primes (Obsession). In that case Qui-Gon's the weakest of the six. He could last a while against any of them, though. Lets say he fights Grievous, Obi-Wan fights Durge and Anakin fights Asajj. Qui-Gon dies at the same time that Durge and Asajj die, and then Anakin and Obi-Wan curbstomp Grievous.
Heck, get rid of Qui-Gon, then it'd be a pretty even thread with just Anakin and Obi-Wan.