how can you make someone from your facebook friend list invisible to others?

[the traveler]

this is the situation: i now that these A and B are friends with each other on facebook. A is a friend of mine, B is not. So in A's friend list i cannot find B, while if i open B's page (closed for me, since we are not friends) i can see A in mutual friends. How can it be possible?

[Lee Kemp]

It could be that B has blocked you? Not sure, either that or there is a glitch or something. But it is impossible to hide a friend from others unless they block you I think.