How to block personalized external domain

[MDF3]

Good morning to all, I'm new in PMG. I need to block external domain. For example I need to block all the domains that contain *pic*.
How can I do this, thanks.

 

[itNGO]

Should be possible in the transport rules directly with a customized main.cf in postfix, but currently not in the web GUI.
Or maybe create a Regex for Domain in the Blacklists.