if you add a server on your network and it uses the same public port as one you already have live - then the new server will clobber the old server and plex.tv will remove the old one
You must always ensure each server uses a different WAN Public port. Some routers do not allow you to have different WAN and LAN ports in a port forward and so you are stuck with only able to have one server
But most routers do allow it and so your setup must be like this example
PMS 1
Port Forward Public Port 32400 to Local Port 32400 for 192.168.100.119
manually specify port ticked in settings and 32400 entered
PMS 2
Port Forward Public Port 32410 to Local Port 32400 for 192.168.100.111
manually specify port ticked in settings and 32410 entered
