http://ca.ign.com/videos/2013/06/11/...n-live-e3-2013 @3:40
IGN: "How many Players does it support?"
Ryan Barnard (Game Director): "A full group for us right now is four players plus a companion drone. So, that's what you'll be playing with if you were out in the open world in New York, but there's areas throughout the game where you can run into tons of different players."
There is a new interview out that releases some more info on the whole group and pvp situation. When you join a group you are tied to the player that has played the furthest through the game. You will be in an insulated section. So you could have as many people as you wanted on ts or vent and they would never see each other in game. There will be dark areas that the pvp takes place it will be seamless entry and exit. But you will be matched pvp wise to your groups make up....
This sounds more like WOW's pvp matches. There will be an area that the game matches groups against other groups as they go toward's a mission goal... Two groups both going for the police armory because it is critical etc...