Do you mean you have a plugin which gets netstat info and stores it as a metric?
You can interface with the Hyperic Server using HQApi, documentation on how to set it up and use the Java interface can be found here: http://pubs.vmware.com/vfabric5/index.jsp?topic=/com.vmware.vfabric.hyperic.4.6/Introduction_to_HQApi.html
Adar