Advice on connecting 2 vehicles to 2 GCS instances

Can someone offer advice on the best/simplest way to connect 2 airplanes to 2 GCS instances (e.g., probably on separate PCs), so that both GCS’s display both airplanes? I would like for each GCS to control one of the 2 airplanes, and display both airplanes. I expect that both GCSs would be on a common ethernet network and would forward MavLink messages to each other. I also expect that each GCS/PC would be connected to its airplane via a telemetry modem that is connected to each PC via USB. If that all makes sense, then I think I just need to know how to get each GCS to forward the messages.

Of course, I also welcome any suggestions for a better approach.

I was able to do this by setting up the connections in MAVSDK with forwarding ON, as suggested by JulianOes, in a separate post under MAVLink - MAVLink Forwarding (MAVLink Forwarding)