Make closed groups fully visible to non logged in visitors

I would like to have some groups on my Elgg 1.8 page that are not open to anyone joining them (need to be invited, or if that is somehow possible, admin validated request), but that are still fully browseable/viewable by non-logged in members.

The current settings (I am using the group-tools plugin) only show the groups profile and a small text that the group is closed to non logged in members.

Thanks for the help.