Google Groups has a number of settings that affect group privacy. Here are some of the most common settings for privacy:
In the first step of creating a new group, group privacy can be chosen from the Choose an Access level area at the bottom of the page.
Once a group is created, privacy settings can be adjusted from the Access tab. To get to the access tab, click on the Group settings link to the right of the group page. Click on the Access link to open the settings.