Ego Feed alerts work great. But if you already have a specific room open in the client, any related alerts for that room should be suppressed.
If you right click on a pchat room in the Lync 2013 client, you can broadcast a message. But you can't drag more chat rooms into that list. You have to close it and then select all of the chat rooms and right click. It would be nice if you could drag and drop chat rooms into the list if the dialog box is already open.