1. Menu Bar>Settings>Key Settings
2. In the Key Bindings window, click the "Add" button.
3. In the Define Key Binding window:
A) in the "Key Combination" section, click the "Set" button(s) for your key(s), and,
B) in the "Action" section select "Whisper to", "Channel Pre-defs", and
"Channel Family" to talk to all,
"Parent Channel" to talk to Leader
"Sub-Channel" to talk to wingman
NOTE: I'm very used to admitting I'm wrong, so verify this info just before the session, ok?
Alternatively:
A) Select "Whisper to" >"Player List", and select your Lead from the drop-down list.
Click "OK" and you're done.