Scroll down to see how to do this in Symphony 1.5
In Symphony 2.0:
Blast messages let you send the same message individually to multiple people or rooms at one time. Click the three-dot menu in the upper right of your chat list and select Blast message (figure 1).
Figure 1 Start a blast message
Add chats, folders, or people, type your message and press the arrow to send.
In Symphony 2.0’s Capital Markets mode, blast a message to an entire workspace by following the steps above from inside the workspace (figure 2).
Figure 2 Send a blast to an entire workspace in Capital Markets mode
In Symphony 1.5:
Blast messages let you send the same message individually to multiple people or rooms in a single click. Click + in the top left and select Message Blast. (Figure 1).
Figure 1 Start a Blast Message
Add rooms or people, type your message and press Send (Figure 2):
Figure 2 Send your blast to selected members