I can't think of any way to do this automatically. If there were variables in the Points for Playing dialog for buy-in time or buy-in round, you might be able to do it that way, but then again, that might not tell you anything. If player A was in the alternates list, and bought in after the general field of players, he/she still might buy-in during the first round, so that wouldn't buy you anything. I think no matter how you implement this, without the ability to place certain players into a "main" list of players and other players into a "alternate" list of players, it's still going to take a human eye to determine how to award points to those players.