engine-patches mailing list

Hi, I've been monitoring the pending requests list for the engine-patches mailing list for a while now, from what i could see, no one send mails to this list except automated mails initiated at gerrit (which is pretty much expected). the rest is spam.. this makes a requirement for people using gerrit (code contributors and reviewers) to subscribe to the list, and get all the mails on all gerrit activity. some people do not want to subscribe, and mails on their activity needs manual processing. maybe there is a way to have automated job to run daily/weekly to add all gerrit users to the accept list for this list? then i would change the list to automatically reject all mail from non-subscribers and users that are not in the accept list. what do you think? any other suggestion?