Not easily - you would have to have each client register interest by sending a message to the server, and capture the ip_connectionId header (ip_connection_id on 2.1 and below) from each client. You would then need some custom code to broadcast the message to each client that has registered interest and insert it's connection id in the header.

Just adding a publish-subscribe-channel won't work at all.

We do have an open JIRA issue to support multicasting over TCP but it's not scheduled to be worked on any time soon. Feel free to add your use case as a comment on the JIRA. https://jira.springsource.org/browse/INT-2495