IP block across network or domains - SPAMMING

I'm a reseller and constantly identify new IP's of spammers (heavy spammers, not the normal guys). I know these guys change their IP's after a while but it helps to block it most of the time. They sometimes hit me with up to 1GB of traffic per day per domain.

Our CPanel and the Reseller menu don't cater for IP address blocking over multiple domains. This meaning I must login to each website to add the new IP address manually for every website.

I'm also using other plugins that synchronize data like users and pages across domains.

Any other plugin that anyone is aware of that can also do this > Update the IP to be blocked on one site and synchronize it automatically with the others websites?