Internet Sharing with regular Hub

I have 3 computers on my network sharing internet connection using Windows ICS. Currently have one computer with 56k dial up modem on the network configured as the server. However, now that I got a DSL service which needs to use the network card on the server pc, how do I use ICS using my current hub without buying a router? Can I plug the DSL modem to my current hub? I know I can plug in another NIC on my server pc but why can I not use a regular hub to do a job of a router if I am willingto have the server run 24/7? Please help…