you can maybe do this by checking the current rank in your database and matching it with a list when a user is connecting
just a example you can do a simple if then statement to check the ranks like below
if rank == 1 then -- allow new member
-- connection code here
elseif rank == 2 then -- allow member
-- connection code here
elseif rank == 3 then -- allow senior member
-- connection code here
else
-- dont allow this person to connect no rank
end