You could deploy your applications in the "default" server configuration of JBoss. The default server instance does not start clustering services and hence the multicast communication between nodes would be automatically eliminated. If you are already running the default configuration, you should not be observing any communication unless the configuration has been changed.
For any reason if you are unable to shift your application from "all" to "default" server, assuming that's where your applications are deployed, you could delete the file cluster-service.xml from the deploy folder. This will disable clustering and the internode communication. Load balancing is not automatically enabled, so you would not need to worry about that.
To tell if you are in the "all" configuration or the "default" look for files cluster-service.xml and tc5-clustering.xml (in jboss 4.0.3 in any case). They should be absent in the "default" configuration.
what i've done is set ip_mcast="false" in my xml files under my all directory. e.g.