what do you mean with "site" a data center, an office, an submarine or moon base? What latency you want to check? between two sites or from a central site to all others?
The easiest way: take a node in the site do a ping test and check the latency.
You may also look at the NetPath service. It can check the network path between a Solarwinds Poller and a TCP service (IP address/DNS name and port) on the other site. Only limitation: No proxy or natting should be in between. The NetPath service records the latency and shows you the point in the network connection to the site where you have a problem.
My apologies for the mishap with the sharing, I meant to remove all groups and thought I did and only realised after the damage was done :-(
Appreciate your responses and feedback. Taking this up with a partner to assist with the setups.