We pick b.root-servers.net, one of the 13 root servers (1), and ask it about ns.ge and learn that ge is delegated to four name servers (2), so we ask ns.nic.ge where we learn that ns.ge is delegated to two name servers, including ns1.ns.ge (3), so we ask that one and get the following answer:
Ns.ge uses the primary name server ns1.ns.ge, the two name servers ns1 and ns2.ns.ge together, hereafter referred to as "name server group 1", the IPv4 number 212.72.154.197 only and the backup mail server ns.ge only.
The primary name server ns1.ns.ge only
All of the four domains that use the primary name server ns1.ns.ge use name server group 1. Worth noting is that four of the domains that use name server group 1 use the primary name server ns1.ns.ge.
The two name servers ns1 and ns2.ns.ge together
There are five domains that use name server group 1.
All of those are under the tld "ge".
Four of them use the primary name server ns1.ns.ge. Worth noting is that all of the domains that use the primary name server ns1.ns.ge use name server group 1.
Four of them use only the IPv4 number 212.72.154.197. Worth noting is that four of the domains that only use the IPv4 number 212.72.154.197 use name server group 1.