How do you make "private" fields in profiles viewable by "friends" - using user relationships

I have been trying all the various modules and combinations of them, but I cannot seem to figure out a way to enable users to view the fields that are not made public in the profiles of their "friends". As of now either everyone can see everything, or everyone, including "friends" cannot see anything. What I want is for personal information in one's profile to be marked private by default, but that user's friends can see those fields regardless. Is there a way for this?

This should be a basic "social-networking" feature I would think. Please help! Thanks