How to have group of users only have access to white list websites

[Unchewable]

So I created an alias called "callcenter" for the 20 users I want to only have access to a white list. Then created oplistallowed alias with the websites I want and lastly created a rule to deny all other traffic. The problem is I can't seem to get certain website to work that bounce to different servers. It doesn't help that some of my clients sites don't seem to be fully qualified domain names. Is there a easier way to do this not through firewall rules like pfblocker or squidguard that would only affect those 20 users? The firewall rule would definitely be the easiest but i am at a em-pass.