Interception Caching and Authorizing Certain Domains

[Brent McConnell <emcconne@xxxxxxxxx>]

I use Squid as a transparent proxy for all my internal users and it  
works great... many thanks to the Squid project.  I'm wondering if I  
can block certain domains like (myspace.com or facebook.com) and only  
allow Marketing users access to those domains?   Is it possible to  
have a generic Deny Page that includes a login option that a user  
could enter credentials into and authenticate them against a list of  
approved users for those domains?  Any help would be greatly  
appreciated.

Thanks,
Brent McConnell