If you are in a group chat, and the group has voice capability, you can place a call to the entire group.
The Start A Chat screen appears.
The call icon appears only for groups, not departments. Groups are indicated with a G in their icon:
Departments are indicated with a D in their icon:
When you are calling a group, the recipients see your name and the name of the group that you are calling. This ensures that they know that this is a group call.