Restrict users internet access in ISA server

[Austin]

I want to restrict certain users on a network from
accessing external internet based on their IP address. Am
using ISA Server as the firewall on Win2k server.

I only have IP of users who should be blocked and not of
those who can access. I have tried configuring Access
Policy/Site & Content Rules and also Access
Policy/Protocol Rules but without luck.

Is there any way to block the users based on the available
IP's?

Austin