Yeah or try to use ARMA's own Civilians that can be "triggered" But that way the civis will be pretty "static" and very predictable. And i havent found a mod that actually puts them in a vehicle, to drive around - that works well.
Hmm yeah did not think about the grouplimits! :O But that can be an issue indeed. if they are to "live" on the map, they cannot just randomly be despawned in inactive parts. That would kill the point i think. Hmm, might have to investigate some moar! :)
And i've never had problems with civilians driving in ARMA... ever.