Broadcast to multiple users

Hello,

I have defined in my project to check to see if an existing app is running on the target machine and "gently" close it before replacing it. There are instances where multiple users may remote into the target machine and there are multiple instances of the app running. I've already put in a loop to terminate these multiple instances of the app and I see in the Task Manager that they go away.

I was thinking that I would like to broadcast a warning to the users that an update is taking place and that their instance of the app will be closed.
Is there a way to extract the "User Name" from the Task Manager of the users who are running the app and display a message on their Desktop that their app will be closed?

Thanks,
Joanne