Drifter by x ticks in play from top 4.

[Andy1978]

Looking for some help or any files that you have ther may be similar.
Want to fix the top 4 10 mins before post time. Take SP of the top 4. Then lay first horse from the top 4 that drifts a certain amount of ticks from the SP prices. Price condition is under 10.
Only want to place 1 lay bet which will be on the 1st horse that drifts the required ticks.

Thank you.