Well, they mention the 13th Vasudan Battlegroup and the 12th Terran Fleet. The 13th Battlegroup is based in Deneb, while the 12th Fleet is based at Ross 128. We have confirmed the existance and base-of-operations of the Terran 1st, 3rd, 4th, 6th, and 12th Fleets, as well as the 13th Battlegroup. As it appears, in order to keep a basically equal military presence of both Terrans and Vasudans in the GTVA, there would be an equal amount of fleets to battlegroups, as well as Admirals and Generals.
Also, it is probably the greatest percentage of personal from a fleet that will give it designation--for example, if 1/3 of the fleet is Terran 6th, 1/6 is Terran 8th, and 1/2 is Vasudan 3rd... that would probably be called the 3rd Vasudan Battlegroup.