Not difficult
If you just have the 3 computers on the network then you can broadcast network OSC cues from the show control computer to the 2 headless d.g
/go
or
/cue/1/start
etc sent to
the first 3 common IP address octets and 255 as the 4th e.g
192.158.1.255
(switch off OSC receive on the show control computer.)
For the headless computers use a dummy plug Display emulator so you can screen share those computers from your show control computer
Mic