organic groups membership

Hello,

I'm trying to build a social network with private groups. Only an administrator (me) can make the groups and invite members. Users of one group cannot see or be a part of the other groups.

I am using Drupal 6 and organic groups. I created 2 groups, and when I click "Groups" in the navigation, it does not show any groups. When I click "My Groups", it shows only one of the groups!