Roman foreign units

Im doing some light modding on the unit file and i wanted to give some extra units to roman factions. Like say to julii, some barbarian units to build. And to brutii some greek units to use....etec.
Anyways if anyone has any knowledge of romans using foreign forces in their armies, tell me..

Scippi fielded a largly Greek army against Julius but while they were greek they were armed as legionaires so....

Well, the Empire did use alot of foederati (sp?), but that's far beyond the dates in this game.