How have the Titans clenched division already?

The colts play the jags tommorow, Ten. the final week. If they win both they will be tied with ten. , overall record, div. rec., conference, and head to head. Tennesee is 21 pts. ahead in points scored. They play the steelers sunday, and indie to close out. If indie kills the jags and the steeler d shuts out the titans who just lost to the texans? It is very reasonable to ume the colts could marginally beat tenn in week 17- totally tied with a higher points scored on the season. What magical tie breaker is the Nfl using?