The solution that worked in vanilla Rome Total War was to have more than one Roman faction, allied to each other, so the Southern faction went South, the Northern faction went North and the Eastern faction went East, as those were the only borders they had with the enemy and they all had different victory conditions.

I'd like to see something like that in EBII as currently in EB the Romans' behaviour is just not historical and they are not nearly militarily strong enough compared to the historical situation.