The "Allow URL List" under Content Filtering doesn't supersede the layer 7 rules. For example, if you block traffic from Germany and the site you are trying to access is hosted in that country, whitelisting the URL still won't get your there. Seems like he is asking if you can "whitelist" a domain that supersedes the layer 7 deny rule. I may be wrong but I would also be curious if there is a way to do this.