access internet via dial up modem, other computer via ethernet card

Hi,

I have a PC with windows 98 (1st edition) installed.
On that one I want to keep using my dial in modem for
internet acess.

However, I also have an ethernet card in the PC to connect
to other computers.

In the internet explorer options menu,
I keep using the dial up modem (not the local network).

Now, If I want to access the other PC
(connected via ethernet cable)
[ e.g. http://192.168.123.254/ ]
[ or ftp 192.168.123.254 ]
[ on the LOCAL network ]
then I still get a dial in message box asking for password.

How can I indicate that windows should NOT use the dial in
modem for certain IP- adresses?

Thanks,

Patrick Brouckxon.