Option for shared vision between human players in multiplayer

[dat1337vet]

My friends and I often play multiplayer games versus the AI. Being on the same team however ruins the game as you're forced to share diplomacy and technology as if you were sharing a single civilization. So we end up doing FFAs where we peacefully cooperate to destroy the AI. However, the game would be a lot more interesting if vision could be shared between players so that you can see what everyone is up to. Preferably this could be toggled on or off for specific players whilst ingame. This needs to be added to civ5 as well.