Thanks for answers!
I have a network for remote weather stations: I've been using two types of radios (for point-to-point link or point-to-multipoint).
I'm changing all network radios with routerboards, so I can use a unique device and configure it as needed: the easyest way would be having only two configurations (access-poin and end-point).
To make a more flexible system I would like to use the radios on routerboard as access-point, so I just have to decide if a radio is access-point or end-point, avoiding to enter particular configurations (as entering MAC address as bridge configuration etc. etc.), then I power it and it's all.
The problem is with normal access point I can enter in the network with a normal wireless card (PCs or notebooks), I would like increase security making the network accessible only for routerboards devices.