Pmdg pfd/nd

Our simulators have been designed based on the PMDG 737. Our main PC is running two 8800 GPU's one dedicated to scenery and one dedicated to PMDG's PFD/ND displays. We have a third party software on network PC that is running EICAS displays (this would be changed to PM). Our Flight Director hardware includes GF MCPPro and GF EFIS as well as Engravity CDU/FMC. Our intentions are to eliminate PMDG's PFD and ND on the main PC and to reduce the workload to scenery only. We would add a fourth PC that would pickup the current ND/PFD monitor now on main PC but handled by PM.
Has anyone setup a system where part of the flight systems are controlled by PMDG and the PFD/ND are controlled by PM? We just want to run the PFD/ND external with PM systems and leave the rest of the system intact.

How do you go about making such changes?

Thanks

Rick