Starting Fluent on multiple machine
 

I have Four PC in my lab all of them connected together.
GMC-1
GMC-2
GMC-3
GMC-4
When i try to run fluent on GMC-1 and tell it to use GMC-2:4 It works fine. but i realize that GMC-1 is loading fluent doesn't really calculate with the others, just the three others are working.my host file is like this
GMC-2
GMC-2
GMC-3
GMC-3
GMC-4
GMC-4
because each one has two cores. how can i make GMC-1 calculate too ?
I tried including him with hosts.txt but an error occurs. Am i missing something ?? Thank you