In a 3-way tie they break the 3-way tie and then revert to the 1st step again to break the 2-way tie that follows. The only way that the 3-way tie is completely broken at that step is if 2 teams both beat the 3rd in that step. So if Denver, the Jets and Jacksonville all wind up tied at 11-5 then the Broncos advance because they are 9-3 in conference games. The Jets and Jaguars do not advance at that point because they are tied at 8-4 in the conference. Instead the tiebreaker moves to a 2-way tie and they go back to head to head.
http://www.nfl.com/standings/tiebreakers Here is the link to the tie-breaker formula, if anyone is interested.
