What if TOWTM had all of the behemoths and Randy has all of the little ones. This is also assuming that they have them under control and they are in factions, but I'm thinking that they had two bases. The hospital and the arena. The zombies had already been to the hospital when Kalani and friends got there, the hospital could have been a secondary base, where randy (still under the "control" of TOWTM) worked on the little ones, and the behemoths. after the explosion at the arena, I'm guessing that there was a change in power, slight, but it moved randy higher up and he continued to move up as we didn't see them for a while in the main story line. They could have split off at some point and become two waring faction, but we haven't seen any fighting. They could still be on the same side, but something that happens during the fight at the colony turns it into faction warfare.
Just my thoughts branching off the control of the behemoth and the little ones.