Sould have a "permissons and autority system"... you can have like check boxes next to each members name, so you could mark the permissions... and use custom groups to allow members to use some buildings, like, if you have gatehouses, you could have some players allowed to open same to warehouses, trade carts, castle gatehouses (maybe just the kings guard could open), keeps...
is like to put a perma-personal claim in something and mark who can use that...