See all servers connected to DNS

We've got 2 DNS only servers and a number of webservers that all connect in to either ns1, ns2, or both. When you look at the webservers under DNS Cluster you'll see which of the nameservers it's connected to, but is there any way to see all of the servers that are connected? On the nameservers themselves, when you look under DNS Cluster it says There are currently no servers in your DNS cluster.