wifi SSID vs network sharing

I know that Vista has started to address this issue,
but recently - when I did the McDonalds and other public WiFi tests
I thought of this major concern.... SSID vs networking sharing (on or off)

At home - all the laptops share some portion of files - the public documents at
least.
Vista has added a concept of linking the network SSID name with how things are
shared.

I wonder if there are any tools to perform this task for XP ?

Basically - match the SSID with turning on/off network sharing... all or nothing

ie -
Panera = turn off sharing
attwifi = turn off sharing
homelan203 = turn on sharing