l.a.c.
Language Acquisition Center
Group Call
The "Group Call" feature is very similar to the "All Call" feature. The only difference between the two is that with "Group Call," you're talking to just a specific Group Type(A, B, C, D, or L) instead of the whole class.
To talk to a specific Group, select the group the you want to talk to(A, B, C, D, or L) and press the 
(Group Call) button.
The "Group Call" button is located to the right of the indicator that tells you which Group you have active.