You can do this, just set your phone to Do Not Disturb and then set it to "allow calls from my contacts"
I guess I'm going to have to fiddle around with when the wife gets home and gather some empirical evidence.
Indeed it does, which makes it a non-solution for me. I apparently have the same desire you do - an option for voice calls to go direct to voicemail unless they are in my favorites list, without having to use the more general Do Not Disturb mode.