We had this happen a few years ago and this is how I solved it.
Pick team with higher points to move on, but link them to team they tied with. This week, if team 1 wins, but team 2 would not have won had they moved on -- team one collects all of prize or moves on alone.
If team 1 wins and team 2 would have won, they split winnings evenly or move on and stay linked.
If team 1 gets money even for losing, team 1 gets it all if it outscores team 2. If team 2 outscores team 1 in losing situation, they split the winnings.
If team 2 would have won the whole shabang without team 1 and there is no payout for losing, well that is just tough ****.
If team 1 loses and team 2 would have won, team 2 moves on ahead of team 1's foe.
So basically, the team these two would play has to beat them both to move on, but, hey, that is life.