I think you can do that ironically if you use Twillio as your primary incoming phone number.
Oh my goodness, my employer uses Twilio as our phone provider. If people started blocking Twilio, then for example a customer might call our support team to ask a question, and then after we research the issue we would we unable to call him back. So I sure hope that doesn't become a thing... whew
Well if Twilio is facilitating robocalls, I hope it does become a thing. Then maybe they’d want to stop robocallers from using their service.
not at the client device level like your cellphone, no you can't. Would have to be done by your carrier at the SS7/PSTN level which as an individual phone system subscriber, is totally opaque to you.