Have them configure a VPN into the secure surveillance network. There are other things you can do but I would recommend the VPN.
KV - What type of facility? For critical infrastructure locations such as an airport or utility plants, it's generally not a good idea.
Why are you connecting the VMS to the internet, for remote access?
Jason - yes, VPN is something we are using. Thank you.
John - We have church type facilities (Hindu Faith Based Organization). We had them connected to perform Windows Updates and Software Updates on the servers.
Forgot to mention that all these servers are behind CISCO ASA Firewalls.
Well that should be simple. Just have them configure their ASA to only allow connections outbound to the microsoft update servers and whatever update servers you need. Cisco ASA makes that easy.