The "few seconds" you so eloquently mentioned is actually much longer than you realize. It takes about a few hours to set them all up privately, including setting-up the usergroups, usergroups leaders, set the viewing permissions, test them all to make sure they are correct etc etc.
They are now set-up.
People will have to go to the
Group Memberships manager in their "My Account" page, and select the group they want to join. classical_hero and DaveMcW have been set-up as group leaders for ALL groups, and will have to activate / approve each person joining manually.
Once you are a member of the particular group, the private forum will be visible at the top of this forum.