Remote IP Block Master List

I would like to vote for a remote blacklist IP list. That way, if I have 100 customer websites, and I notice one hacker.. I could just update the master list and ban that hacker completely from all sites.

I currently have a large amount of sites, and notice that the hacker goes to each site and attempts to login. I then have to manually block him from each account via RSFirewall which is tedious.

If I had one master list, I could add his IP and be done with it. Alternatively, if this cannot be done, maybe I can have a single email address which is accessed via RSFirewall via Pop and it adds any IP it finds to the master list.