40 ball is a very popular game in the multi-team groups I play in. There are several variants:
40, 44, 48 Ball- This allows for the teams to ignore how many balls they take on each 9, they just have to keep the specified number of scores for the whole round.
20, 22, 24 Ball- This variant requires the specified number of balls to be taken on each 9. Even if you start in a shotgun, the number of balls on the front and back must be followed.
The concept of the game is simple. At the completion of each hole, the team must decide if they are going to keep any of the scores for the hole to contribute to their team score.
Those holes they want to keep they checkmark, and the team must watch what they do as if they don't take many scores early, they may find they have to take scores later they wish they would not have.
Example:
The 4 man team has arrived at hole 6. A par 4 and two of their players get strokes on the hole.
Once the group plays they hole, here are the scores:
Player A: 7/5 (a 7 but net 5 as he got 2 strokes)
Player B: 5/4
Player C: 3
Player D: 5
The group must decide what scores to take. Sometimes the commissioner may adjust the game settings to require every team to take at least 1 score on every hole. Lets assume for the example that is in effect. They must take at least 1 score.
Right away the team knows they are taking Player 3's score, it was a birdie. But they also decide to take Player B since it was a net par. The other scores are bogey or worse, so they decide to skip those scores. So in TeeRival, they place a checkmark next to the scores they want to keep.
TeeRival keeps a live leaderboard for the scores and keeps track for each group how many scores they have taken. It also forces teams to take scores when they have run out of holes and must take scores toward the end of the round.
The team that has the lowest score relative to par.
In the settings of the game you can also decide if you want to reward teams that win the total, or if you want to have payouts for best front, back, and total. That is how most groups play so that a team that played bad on 1 nine, still has something to play for on the second 9.