Update: The method I mentioned above does not work like I thought it would. The only way I know of is to program a button to turn on/off *immediate* forwarding. Here are the steps for that:
1. #208 - Line Coverage Ext. - Set appropriate lines to the ext. you want to control forwarding
2. #322 - Remote Forwarding - Ext. # - 1 Assigned
3. Program a speed dial (80, 81, etc.) on that ext. to the outside number.
4. Program a button for F11 to forward that ext. to the speed dial number you chose. (example: F11 10 80)
Then when you press the button, the feature turns on and all calls are forwarded. It will take up 2 lines for each call forwarded (1 for the incoming call, 1 for outgoing forward). This method DOES work for us.