For some reason it made me think of the iConnectivity interface that has the automatic failover between two computers by using a sine-wave generator plugin to detect if one of the computers goes down (and then switches to the other).
In theory you could use G8 to receive a sine wave from another GP instance/pc and then use the midi message generated by G8 to switch/activate the other GP instance/pc (if the sine-wave stops).
I did a quick test on the same machine using two GP instances and the Melda MOscilloscope plugin (routed on virtual audio ports). I intentionally crashed the first GP instance (I have a bad VST3!) and it enabled the audio output of the second instance immediately. Anyway, I was bored 