bsp bet on selection - how to check?

Hi, I am trying to figure out how to check if a selection has had a lay at SP bet placed.

Here is what I am working on, hopefully you can help/suggest...

I am using dogs
I use a selections file (as I normally do)
I will place up to 2 lay at SP bets, most likely it will be 1, but 2 can happen if the conditions fit
I am aware that you cannot set a minimum price for a lay at SP bet, so, I use a workaround in the conditions of the trigger :
selections lay_price greater than myMinPrice

So, for example, say the constant myMinPrice = 14.

And so, if the price rises above 14, a lay at SP bet will be placed, with whatever liability - at or greater than the £10 minimum.

Now, as this is dogs, prices can be quite volatile, and I did actually have a bet placed yesterday, where it reached 14, but went off at 5.2 - and the bugger went and won! (fortunately still on test) As it is dogs, there is no In-Play, so no chance to trade out, and so, I decided I wanted to use the following conditional...

IF the selection has lay at SP bet against it, and subsequently, the lay price falls to 11 or below, then I want to place a back bet to offset the potential loss, and so, I was thinking of the following:

check the selection has a bsp bet against it
if it does, then use the conditional :
lay_price equal or less than 11
and set the amount to back as lay_liabaility/(near_sp - 1) - this won't be super accurate, but it will at least offset a potential loss, by a reasonable margin.

BUT, I have no idea how to discover if a particular selection has a lay at SP bet against it. AND, given there can possibly be 2 bets, then I want to do this for each selection.

Now, for those that have read my previous questions, you will know that I am a big fan of using text files to help me, and if I were forced, I could have the lay at SP trigger write an entry to a file, and then have the lower odds trigger read this file and check for the selection, and this is probably the most logical way forward, BUT, it is painful to have to do this if there is an easier and much more eficient way to do it directly through triggers and variables.

Can I do this, or can you suggest alternatives?

Many Thanks

Hi
all matching selections
selections lay sp amount is greater than 0
will find all selections with lay at sp bets