Sorry this might be an easy question, but i started to play around
access rules for the first time.

What i want to achieve is the following result:

1. ALL users are allowed to access all URLS (easy one)
2. Deny IP Range XYZ to use the proxy to access all internet sites but

allow them to access a number of specific websites , and so on

The problem is the iprange is not really an ip range but a number of
with mixed addresses from DHCP (which will remain the same though)

Any help even just a link to a good "First Start" link page would be