I think that combat starts once you're in a certain range of an enemy. But I don't know what that means if party member A reaches that minimum combat range, but party member B is a few steps behind A and hasn't yet. Does B also get drawn into combat? Or are they still real time until they move forward a bit?
No, if the distance to B is large enough he/she is not drawn into combat. In a multiplayer game that person can go do whatever he/she likes. Even start a fight at a completely different location.
When getting close enough to the combat of A, he/she is drawn automatically into that fight.
