Automatically, seamlessly block Google-suspected spam calls

The Google Phone app now reports when a suspected call is spam. Right now when I receive such a call, I have the choice to block that number. But what I'd like to do is pre-emptively set it up so that any such call is automatically blocked without my intervention. I've investigated apps like Root Call Blocker Pro, and while they seem to do the silent, transparent blocking I'm after, it seems to require me actively maintaining a black list, entering the phone numbers I want to block. I'd like to rely on the Google's suspicions to block them. How can I set this up? Alternately, might this be something my carrier can handle on a network-level? I'd be happy to pay for a relatively cheap app or work up a tasker/etc solution, but I'd rather not pay AT&T for a monthly service.