If 3 teams tie, they do not send one to the WC game. Teams are designated as A,B and C. Team A plays Team B. The loser plays Team C. Both winners advance to the WC game.
Home field is determined using head-to-head records as the first tiebreaker.
MLB playoff tiebreaker rules
WWW.MLB.COM
With the 2022 expansion of the postseason field from 10 teams to 12 teams, tiebreaker games will no longer be used to resolve ties in the standings at the conclusion of the regular season. That means no more “Game 163.”
Instead, ties will be broken by math, with specific outcomes