SOMETIMES, it can happen. My rugby forum for example is an authority on the subject, the BBC linked to my forum, from their Rugby section, and now my forum outranks them for the name of their show!
These are rare though, and what you are referring to is the local rank effect, and possibly the HITS & Hilltop algo's. Safe to say though that the only time the scenario you are talking wbout will happen is if the two pages are close together in the SERP's.
e.g. Say the two pages in the example page a is naturally position 1, page b is naturally position 2. Local rank would say 'according to US, the order is A=1 B=2 BUT local rank dictates that if age A cites (links to) page B, then IT thinks Page b is an authority on the subget. So we rank Page b above page A.
this is why it is important to try and get links from sites that appear in the top 20 for the phrases you are targetting.
General comment: Local rank isn't to be confused with local search or google local One relates to the geographic positions in the world long & lat. Local rank refers to pages that appear in the neghbourhood of the SERP's
