I would suggest writing a VBscript which starts at login.
have it do the following (pseudo code)
vpnconnected = false
loopvar = neverstop
do until loopvar = stop
pull the SSID of the connected WIFI network
if SSID is in a predefined list of networks to vpn from and vpnconnected = false
kill all openvpn.exe and openvpn-gui.exe
run openvpn-gui.exe --connect %openvpnfile% (where %openvpnfile% is the ovpn file you want to use to connect)
vpnconnected = true
end if
loop
I'm doing something like this with our login script. the login script checks to see if the user is local, if they aren't it automatically kicks off the openvpn-gui.exe, passing it the end user's OVPN.
hope this helps!
Taylor