sorry, still can't get it

i have 3 ranks: 1=Junior Member, 2=Member, 3=Senior Member
and the default group ranks (admin, mod, guest).
how can i set to only show a board to e.g. "senior members"? when i promote a user to level 2 and add the title to the secondary usergroup, i should have a usergroup "members", when i add 3rd level, i got "senior members" - is that right?!
so i need to set the ranks "member" and "senior member" as usergroup in vb with the special permissions?
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when i now have a group "specialposter" and got them mentioned in "Override Level Ranks on a primary usergroup id basis", these groups aren't touched by the plugin?!
so maybe this is the reason, why the people of this group aren't updated by the plugin?
thanks?,
thomas