Site and content rules are an integral part of ISA server, and require a good understanding in order to configure ISA server to perform the functions described below. These rules are a very powerful part of ISA and mastering them will help you to get the results required by your organization.
Destination sets: are collections of one or more computers or directories on specific computers. When designing access policy rules destination sets may include computers that are not on the internal network. The contra is so when designing Web and server publishing rules, these destination sets normally reside within your internal network.
The result will be when the user tries to access the unscrupulous website, access will be denied and he will then be redirected to the company policy webpage.
This can be useful when denying specific content that you do not want users to access on a particular website.