The ximble chat option to send massive messages is good, the problem is if the employees wont enable their notifications to push in their phones for ximble, the message will go non noticed. Instead massive sms text. This feature together with the chat will be perfect, no excuses of not getting the massive messages.
Why should we implement this
It will be a complement to ximble chat.
I would recommend using announcements on the dashboard for more formal communication to ensure that people received it via SMS as well as via push/email. Adding SMS alerts for chat, which can be used in a bit of an informal chit-chat manner between the users themselves (rather than just a manager->employee communication) may impose a problem for a lot of users if they start recieving SMS for each message received.