Okay, Ive been trying to give all the Eastern Roman territories to the Western Roman Empire with the same armies (with a few changes due to difference in the two unit rosters)

Now, i have managed to get all the Eastern Roman territories into Western Rome's hands, and removed the Eastern Romans from the map...and i can get the armies on the map as well, with one exception...

I can't seem to figure out how to combine the two factions Family members, which i think is important, due to half the empire otherwise lacking Generals and such...so, how do i do it?