In order to allow non-TCNJ Users to your Google Group, you need to first enable that option by following these steps:
- From your Google Group, go to the "Settings" Section
- Scroll down in the "General" section you start in and you will start to see options regarding who can join the Group
- Under "Allow External Members" select the "On" option
After checking that box and saving the changes you have made, you will be able to use the "Invite members" and "Direct add members" options to add members outside of TCNJ.