Ringtone for some and not others

How do I make the ringtone for people in my address book different from those who are not without changing it on each entry one by one?

Somewhere else on the forum someone said "Set the default ringtone on the phone to the not in the address book

ringtone. Set the ringtone on people in your address book to the in the address book ringtone."

I've been unable to find such settings.

I have the latest iOS.