Connecting to wireless access points via MAC address

I have a Dell laptop running WinXP. The wireless net card is a Dell TrueMobile
1400 dual-band mini-PCI card. The environment in which I am trying to connect
features numerous access points (up to 12 can be monitored from some points),
some restricted by necessitating a VPN connection, others pretty much wide open.
Also, there usually are dozens of client machines trying to connect or connected
at any given time (it's a classroom building). Sadly, every AP in either the
restricted or wide-open group has exactly the same ssid, though they do use
different broadcast channels (1, 6, 11). The XP connection s/w seems to
consolidate all of the APs with the same name and show only one AP. The Dell
connection utility has a site monitor that shows all of the available APs and
their signal strengths, MAC addresses, etc.

I have had some limited success in connecting to APs other than the one showing
the strongest signal (which seems to be the XP default) by going into the card
configuration dialog and resetting the channel on which the card tries to
connect. However, this does not seem to _force_ the card to connect on that
channel. It seems only to allow it to connect to something other than the
default (which likely is the one to which most people in a given classroom are
connected), and this does not always provide a reliable, stable connection.

So, long question (sorry) short, is there a way that I can use the MAC address
of an AP to force my machine to connect to that particular AP? The Dell s/w
does not allow me to choose an AP from its site monitor list and connect to
it.

Thanks for any help,
Blue