See at the docs to learn what JmmDNS is: http://jmdns.sourceforge.net/apidocs/javax/jmdns/JmmDNS.html
To get all IP Addresses where the service is provided, you just need to add one listener for the service. It should be notified for every service available in the network.
So the method serviceAdded(ServiceEvent event) from the ServiceListener will be called multiple times. But you have to trigger that the service will be resolved and you have to actually save all IP addresses yourself.