Broadcasting a message to multiple resources

To be honest I am not completely sure if this can be solved solely from the server side. We are using Exodus as client app. However, in our Windows-Network we often have users who are logged in from multiple computers at the same time. This is no problem since we can avoid conflicts by setting resources accordingly. However, when someone is logged in in one place and then logs in on another machine, only the latter computer receives messages. Is it possible to change this behaviour by default?

We would like to have the message pop up on the screens of all computers from which a user is logged in. Is this possible?