In our network, we needed an alternative to e-mail, in case there was an outage and information had to get out. The solution that was suggested is using IM. However, we don’t really want our users to be using it as a primary means of communication. Is there a way for IT Admins to send out broadcast messages when necessary, yet restrict other staff from using Spark and OpenFire as a way to “chat” with their buddies? We want to have our e-mail system be the official means of communicating.
You can try restring messaging with Packet Filter plugin, but really, you need something else for that than using a chat platform and a chat client and make it not work actually.
if you’re a windows environment, you could just blast a message out using windows built in service from command line. check out msg.exe