Web Protection: Limit Web proxy users from Internal sites.
There is no way to forbid access to internal networks over The Web-Proxy.
It will be nice if we have the opportunity to grant the http/s or ftp access to other ASG Networks.
Bob Alfson commented
Have you asked this question on the User BB? http://www.astaro.org/
If I understand what you neeed, I think it can be accomplished today.
Cheers - Bob