Resolution:
Please follow the steps below to monitor more than one EMS server thorugh EMS Manager:

1) Open the Display Builder > Tools > Options > TIBCO EMS Administration > TIBCO EMS Servers.
2) Add the servers at the above location and then hit “Apply and Save Servers File” followed by “Save” and then “Yes” to make it run from anywhere.
3) You have to restart the builder for changes to take effect.
4) After this make sure that the changes did get persisted in the “servers.xml” under the “demos” directory in the RTView install directory.
5) Finally, start the EMS Manager and check if you see all the servers.