Can I set a ringtone for all calls that are *not* contacts

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http://forums.androidcentral.com – I've searched but can't find the answer. I know I can set ringtones per contact but that's not what I'm looking for. What I want is a ringtone set for all callers that are *not* contacts that is different from my default ringtone. In the end, I want a few personalized ringtones for a few family members (done), a ringtone for all other contacts (default ringtone - done) and one for all calls that are not contacts. Anyway to do this? (HowTos)