How about this one!

Operate ONLY on metropolitan meetings in Sydney or Melbourne on races between 1000 and 1600 metres and with between 7 and 20 starters

THE RULES

1) Eliminate any horse that has not won at least three races.

2) Eliminate any horse that is not in the first or second favourite in the betting with 15 minutes to start time.

3) Eliminate any horse that hasn't started within the last 30 days.

4) Eliminate any horse hasn't won within the last calendar month.

5) Eliminate any horse that wasn't favourite at its last start.

6) Eliminate any horse that didn't win or run a place at its last start and was beaten by more than 2 lengths.

7) Eliminate any horse that didn't win or run a place at its second last start.