Hi NS24,
From my experiences on the I&A server (Semi-regular player), most players tend to 'Rambo/Lone Wolf' the Main Objective ("AO"). Sometimes groups do form, but usually you get your loadout, bundle into the nearest transport aircraft and then deploy at the LZ at the AO and fight your way to the HQ. Sometimes it can be different depending on terrain and situation, but that's usually how it goes for me. The squads in I&A don't really get used outside of specific roles (Pilots/Medics/Snipers/Ironside Etc).
I think you'd enjoy engaging in some of the Side missions if you want more squad-based activities on I&A. These occur regularly (Usually spawning 15 mins after the last one ended) and require more coordination and communication than the AO gets. There are a few players who gravitate to Side missions when they occur (*cough cough* Hamish [TEF], Kyroe for example *cough*), so don't be afraid to ask in the blue Side chat if anyone is headed to Side mission.
NOTE: There is a Side Base located NE of the main Base where a Hummingbird and Offroad spawn for Side teams to arrange their own transport.
If you do end up headed to a Side mission, do try to make contact with other players at Side or on their way. Side missions usually require multiple players to complete, and the time-sensitive missions require coordination to enable maximum time to complete it's objective. The Rambo/Lone-Wolf approach doesn't usually work at Side missions, but when a group of players come together on Side it's a damn good feeling (Especially when the reward is something awesome, like a Mortar Boat!).
Good luck on the I&A server, don't be afraid to jump on our TS (ts.straya.life) as some players working together will be on there to coordinate.
See you round Altis!