Try:
Transfer 800
Passcode
Press 1
Press " Speaker"
Press " 601"

Scroll to the group you want using the volume and 3 soft keys on the very top of the phone.

Once you find the group, you must locate the " MEMBERS" section by scrolling. I believe its numbered 1-32. Find an empty slot then add your extension.

I think this is how you do it unless you have a agent group setup then you would you could assign yourself a button to just login or logout as you please. You may want to look into this if you are having to switch between being in a good and being out of a group every day.