Cross Genre, Cross Vendor Game Communication

I had an idea for a game, or game platform really, a long time ago. I've always been a big fan of really in-depth flight simulators like Falcon 3.0 and Falcon 4.0. I've also loved infantry-style first person shooter games. Some people like tank simulators; others like submarine games. What I had thought of for a cool idea would be to allow all these types of games to interact together within the same persistent game world, kind of like Battlefield 1942, but on a much larger scale. Wouldn't it be really sweet if the planes flying over the infantry heads were pilots playing Falcon 4.0? And the tanks rolling by were full tank simulator players? Battlefield came close to my vision, but in a much more stripped down form. Those of you in the gaming industry, has an idea like this ever come up? Coming up with an XML-like communication standard across games so they could run within the same gamespace? I'm not sure if I'm explaining my idea enough or if this makes sense. My original idea was to have a single game, similar to Battlefield 1942, that had all those simulator games in one: a full feature flight sim, infantry-style FPS, a tank sim, etc. But I realize that would be virtually impossible, I think. Thinking realistically, I figured those developers that make really incredible flight sims could do what they do best. Each developer would stick to their expertise and make their simulator, but with an open communication standard so all the simulators could talk to a central server than ran the game world/campaign.

It's late in the work day so this isn't really making a lot of sense. I'm really just thinking while I type. To me, this sounds like a cool idea, but probably an impossibility knowing the way large game companies operate. Maybe the open source community could handle it.