Well, if you have some basics in making dll, you can do something rough like "if any vessel come within X meters from another any vessel (except self), then make the 2 vessels vanish". That would be my best guess. The problem is that Orbiter will have to scan constantly for all the vessels in the simulation. No problem when there is 2 or 3 vessels, but troublesome when there are dozens of them (and you quickly get there with space stations made from modules).