How to set s condition in Card Derby?

What conditions (not even sure it is a condition) would I need to set if I wanted to place a bet on the third Favourite depending on the values of the handicap points of the Favourite & Second Favourite and both would have to meet the condition?

In essence I only want the bet placed on the selection when the fav and 2nd fav  hands have a certain number of handicap points.

Thanks