In a three-way tie, head to head results matter only if a team has beaten or lost to both of the other teams. Since conference records are even, common game results will be looked at.
SD beat Denver twice, beat Tennessee, beat Cincinnati, and beat Buffalo (5-0)
IND beat Denver, split Tennessee, beat Cincinnati, and beat Buffalo (4-1)
BAL lost to Denver, beat Tennessee, split Cincinnati, and in this scenario they'll have beaten Buffalo (3-2)