YOu need to go to descr_strat File in the imperial campaign folder and the the roman headings from this:

faction romans_julii, comfortable caesar
Roman senate superfaction
denari 5000


To this:
faction romans_julii, comfortable caesar
denari 5000


You'll notice that i've removed the superfaction status. Do this to all of the romans including the senate and that should do the trick.

Warning though. Dont Click on the senate floor or title and offices tabs while in play or you CTD. but other than that its fine. ALso one more thing if you like longer campaings as i do you change the start date to much earlier i start my games at 470BC and had no problems.