The procedure is essentially exactly the same. You'll navigate to the "KEPServerEX Monitoring" module, and click the plus icon to add a new server. It will again generate the configuration for Kepware for you to copy and input into that instance of KEPServerEX.
Some extra troubleshooting for you:
1 - If the remote KEPServerEX instance can't connect to Kinex, ensure you can ping the machine that Kinex resides on
2 - If you can't ping the hostname, try it again with the IP address of the Kinex host
3 - Assuming one of those two works (if not, this means that they're not on the same network (which complicates things a ton more)), make sure that whichever port Kinex occupies on the host machine allows incoming connections.
Let me know if you have any more questions,