There are some implementation details that the KVM maker would have to get right, but if they don't screw it up, it all works as expected. Good KVMs already lo

There are some implementation details that the KVM maker would have to get right, but if they don't screw it up, it all works as expected. Good KVMs already look at the keyboards they have connected, present separate virtual keyboards to connected computers, and route keystrokes explicitly based on state. You just need them to count the keyboards connected to them, and present a separate virtual keyboard for each downstream connected keyboard, so that the connected computers can tell which keystrokes came from which keyboard.