It's in the tournament rules.
"In the event of a tie, the better scoring entrant between or among the tied entrants will be the entrant with the lowest combined score for the final six (6) holes of the Game. If any ties remain, the better scoring entrant between or among the remaining tied entrants will be the entrant with the lowest combined score for the final three (3) holes for such Game. If any ties remain, the better scoring entrant between or among the remaining tied entrants will be the entrant with the lowest score for the 9th hole in such Game, and any remaining ties will be determined by identifying the lowest scoring entrant for each individual game hole, in sequence from 8th through to 1st, as is necessary to determine a winner and, if any ties remain at that point, the earlier-submitted entry between or among the tied entries will be deemed the better scoring entry."