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.