Twilio is kindof trivial, they have a GUI-builder thing that might let you do "something like that". There was another discussion w.r.t. "90-y/o parents are getting scammer calls 24x7" and they implemented a "most-recent-number blacklist" along with the usual "allowlist". It's genius!

Basically: if ( in_allowlist() || called_twice_in_a_row() ) { allow_call() } else { respond_with_beep_beep_problem_please_retry_your_call() && hangup() }

...all humans (eg: doctors offices, appointment schedulers/verifiers, etc) are like: "huh, phone system must be f'd up right now" and call right back. All mechanically dialed spammers just $PHONE += 1 and continue dialing. Son kept an eye on the "called twice" and added them to the allowlist (or maybe you could just auto-add if they ever call twice, and then validate / name / prune new entries once a week or so?)