U can try this configuration :
Comp 'A' :
Set the IP address with "192.168.0.1" for the first Nic and put "192.168.0.2" for the second Nic.
Put subnet mask with "255.255.255.0" for noth Nics ( it ussualy show up it self automatically after u enter the IP address.
Leave the gate way field blank , and then u put the primary and secondary DNS on both Nics ( example "202.158.X.X".
And then hit the advance button and select the "WINS" tab menu on the top, and fill the field with the first Nic IP address ( example '192.168.0.1 ')
and then u may restart if the system need to reboot the system, if not u can follow the next step.
After rebooting ( if ur comp need to restart ), right klik on 'My Network Places' and select properties. Then u select the share tab menu and choose 'share internet' and u will find 2 Nic's name on the fiels ... select the first Nic name.
Comp 'B' :
Same with 'A' configuration, but on 'B' u have to put gateway field with the first Nic IP address ( exmp '192.168.0.1 ) and then hit advance button and fill the WINS with the first Nic IP address.

I hope it works and i could be wrong about this mate.

Good Luck