Why two? If network is the issue, just make sure NMC server has VLAN for each network and add servers as per networ defined and accessible from NMC. Unless you have an issue where you have older NW server and newer one so in theory you must use two different servers... I believe that won't work and you won't be able to run two different servers on single box.
You can run two NMC versions in single server.
You have to have two different NMC servers.
Why you need two servers? Newest NMC version can mange older Networker server version.
That sounds good.
We need to use 2 different NMC versions because with NMC version 220.127.116.11 Build 510 we have recieve an error message without any entrie after opening a group in the monitoring. It is only a blank window and you you have to restart the whole NMC to go on with your work.