Android has a similar feature in its Do Not Disturb mode. If you're not already in my address book, my phone simply does not ring. Everyone I need to hear from

Android has a similar feature in its Do Not Disturb mode. If you're not already in my address book, my phone simply does not ring. Everyone I need to hear from on a moment's notice is in there, and everyone else can leave a voicemail. It's maybe a bit sad that it's come to this, but the robocalls are rampant and this is the only solution that even puts a dent in the volume.