43 cent's question is "Is this possible?" - meaning can we set different behaviors (levels of aggression, etc.) for different civs that the AI uses throughout the game with that one flag.
Like Ozymandias, my gut says no - the setting is locked at the same level for all civs - set in-game in the opening screens after a biq is selected to play. But someone with actual experience finding things that Firaxis didn't give us direct access to in the standard editor may know differently.