Please accept my apologies, Mcbee, as I have not expressed myself well. This is what I want to do :
(i) I set conditions which a horse (s) has to meet for me to back in running,
(ii) MFP backs the horse and then, hopefully, lays it producing a profit ( let's say I am looking for five ticks profit)
(iii) If I successfully green the first selection, I want to attempt to back and lay another qualifying runner in the hope of making more profit, BUT
if the first selection is not greened, I want to bet the second horse as a straight back bet without greening.
I want to avoid the situation where my second selection wins the race only for me to have reduced my winnings from it by greening up. If the second selection wins the race, obviously my first backed runner loses a unit stake for me. By observation, I stand a better chance of making an overall profit if I do not green the second selection.
I currently use a trigger which has backed and greened up to five horses in a single race. When this happens all is well, however, things go wrong when lay bets are not matched.