area culture in the Grand campaign

recently played the Kingdoms Britannia Campaign and i;m wondering is this possible to impliment into the Grand Campaign. This would mean getting rid of the Pope, also the heretics and Inquisitors, which would'nt be such a bad thing. The culture system could be a problem as we can only have ten different kinds, so i'm thinking we could have area cultures, an example would be to have Milan Sicily and Venice as a Roman culture, Portugal and Spain as an Iberian one, Egypt the Turks and the Moors as another. I suspect this could be quite a challenge to my somewhat limited modding abilities so any input would be much appreciated. The files below are the ones that would most likely have to be modified, i'm pretty sure that there's quite a few others i've missed.



{world folder} campaign_script descr_mercenaries descr_strat
[Text] export_buildings missions export_ancillaries religions export_vnvs expanded.txt shared.txt strat.txt tooltips.txt
[Data] descr_campaign_ai_db descr_campaign_db export_descr_buildings export_descr_buildings_enums export_descr_ancillaries export_descr_ancillary_enums
export_descr_character_traits descr_cultures descr_missions descr_religions descr_religions_lookup descr_settlement_mechanics descr_sm_factions export_descr_vnvs_enums

Soul Reaver