It's covered in Scenario 4. If none of the 3 teams has a winning record against each of the other 2, then it's winning percentage among the games played between the 3 teams.
For simplicity's sake, let's assume the season series is 18 games, and the Hoofties beat the Nimrods by the same margin that the Nimrods beat the Jackwagons.
Hoofties 12-6 record vs Nimrods
Hoofties 9-9 record vs Jackwagons
Nimrods 12-6 record vs Jackwagons
Cumulative record among the 3 teams:
Hoofties 21-15
Nimrods 18-18
Jackwagons 15-21
Therefore it's N vs J on Monday, winner plays H on Tuesday.