Custom Broadcast message with custom time expiring

I like to use the customer broadcast message for internal messages as it might happened. not everything might be an emergence. Example: when we have a schedule downtime for a server, I would like to use the boradcast message feature to display a message on the screens, but not have the title read "EMERGENCY" which is what it does now. I would like the title of the broadcast message to be what the name of the alert is and currently is has preset duration. 1,2,4,5,12 hours. Would like to be able to put in the time when the message expires.