Groups that are publicly visible but private in content

First things first: Thanks a lot for your great work, without OG Drupal wouldn't be half of what it is for me!

I was updating from 5.x-8.0 while migrating from Drupal5 to 6. The old version allowed groups to be listed in the groups-directory with their content remaining private to group-members. After the update groups configured this way were not private anymore. I had some warnings during the update, but no errors. And nothing that would have made me suspicious in this direction. This easily goes unnoticed, if you test group visibility only with a hidden group, which works as intended after the update.

Now my users say they want this "feature" back. And I support this request. It's a good way to "promote" your group, even if you want to control who gets in. And I think this is even urgent, because sites might brake their security without noticing - which could be very bad, depending on the content. I searched the issues but didn't find anything like this. Also I was unsure if this is a bug-report, a feature-request, or both. Hope I am doing right in adding this issue this way ...