OpenFire s2s inside a domain

In a shell, I would like to set up an additional OpenFire server within my domain and have the servers be able to talk to each other. LDAP is up for both and both servers work just fine. How do I connect them so if someone logs into the new one (We’ll call it NEW-PC) they can still communicate with who is logged into the old one (We’ll call it OLD-SVR)?