the question, while I can kind of understand it, I cannot follow completely the original requirement.
On a simple way: open the port/connection is the first thing to do. But if your users can already connect to the VA server, but they cannot login or they cannot see the right reports, that is a SAS metadata requirement. You might need to register the new users or provide the right permissions to the right group/s.
But let me do a try. I might give you too much information, but I will aim to cover the global scenario:
On my understanding, and please correct me where I might be wrong, is that you have a VA server on a network A/Domain A for your current site (A), your users can connect from site A to the VA server sitting on network A. But your other users (pan-India) are on another network/domain B, and they cannot access on the same URL.
In case network A and network B can communicate without internet, they are just on different network or domain, they you only need to create the network rules and redirections (DNS server, open firewall communications, etc), until you can communicate with the VA server at the 7980 port.
In case network A and network B need to communicate through internet:
You will need to secure internet connections to your network. For that, you have 2 options:
you can put your VA server within a F5 or DMZ, to protect your internal network from undesired hacks. If you need to move the server, you will need to reconfigure some network connections as on step 1.