I am using MT841 Type III modem with BSNL dataone. I have connected my desktop to one port of the modem and the 8 port switch of by office to the another port of the modem. The modem is on auto dial setup and All the computers are using windows xp and are on automatic ip mode and are working fine.

Now what I want to do is to limit the other computers from using the internet at a particular time (i.e. when I need the full bandwidth).

Can anybody help me in this regard ?
Thanks