Im sorry Dominyo but this idea is flat out crazy, I can see where you're coming from but as a person who plays single 80% of the time, running into teams is something i loathe, and if they could become invulnerable to each other then they would be practically unstoppable. I cant count how many times a team would have one member trying to hack me into lunch meat while the other snipes, and the sniper shoots his team mate by accident, giving me an upper hand.
Teaming on its own, is tolerable, but what you're proposing? its just pure madness.