Well maybe not so quietly..
To make a Multi Role Simulation Theatre there's I guess 3 divisions.
Air: The Lo-MAc we know and love now with limited visuals on the ground.
Air and Ground: The middle ground: Choppers and small aircraft
Ground: Ground vehicles, Ships and the Infantryman.
Now lets look at each part in a bit more detail.
Air: Requires long distance views and plotting information of certain objects like other aircraft, larger moving vehicles such as ships and vehicles Already done effectively. But next to no information about a soldier on the ground.
Air and Ground: Choppers dont need as much of a distance view as the "Air" objects do but more importantly high detail on the Ground. So a mix of Air and ground information would be required.
Ground: Requires very high detail up close of other infantry, vehicles and anything within say a 500mtr radius.
So if a theatre was made that was common for all 3 areas it seems to my mind quite possible to only supply the required information to each and integrate them effectively.
For instance the Grunt on the ground doesnt need to know about a high flying jet's radar or flight physics or if it is firing a missile etc. Just its location in a 10,000 meter radius. Maybe seeing a contrail at high altitude or a dot maybe a bit of a sound effect until it comes to say 1000 meters where a profile might be seen. And then more information requested by that client's pc.
At the other end of the scale the high flying jet doesnt need to know about a dumb grunt until hes in stinger range, say 2000 meters and even then all he would possibly see is a very basic human like we do already. The fighter pilot doesnt need to see animated movements and so on.
So..
The way this would be done effectively is to set up protocols for the 3 areas. Each division is developed independently and sold seperately. The Map or theatre for the first person guy who could run around or jump into a truck, tank and so on would buy his game and log onto a common server which the chopper guy or the flight sim guy would also log onto with their own software and terrain maps.
This means you wont have the nicety of being able to jump out of a tank and jump into a jet or a chopper but you will still have a "Study" sims for each.
For this to work effectively the Server software would have to be completely independent of all 3 and definitley just be a dedicated interface that passes plotting information.
In fact there might be 4 servers for 1 theatre. A server for the Air, a server for the Air / Ground and server for ground. These 3 servers are what communicate to the master server. So in effect it would be a 2 tier system.