Is it possible to make the following trigger?

I'm not looking to have this made (yet), but would like to know whether it is possible to setup the following (in a better way than I'm attempting):

I want something that will tell me the probability of each horse finishing in X place based on its price in the win market for any given race.

I've been able to code one that provides probabilities for 2nd place, but want to check if there are other/more efficient ways of achieving this, as calculating 3rd/4th/etc requires substantially more iterations than calculating 2nd (I'm having to calculate iteratively as the number of horses per race varies).

Output required would simply be variable value (e.g. so 'toptwo' would return the probability of finishing in top 2 places, 'topthree' the top 3 place probability, up to at least 4 places and preferably up to 6).

Could such a trigger be made either to operate non-iteratively and/or to do the relevant calculations externally in excel?

The relevant maths can be found here: https://math.stackexchange.com/questions/864823/place-show-and-unordered-horses-forecast-probability-calculation

Hi
Implied probability is (1/r_1_back_price)*100
(if you sum these it is the back book)

so top 2:
selections sorting order is defined by (1/r_1_back_price)*100 
and selections trigger expression match_index is between matching_number-1 and matching_number

top 3:
selections sorting order is defined by (1/r_1_back_price)*100 
and selections trigger expression match_index is between matching_number-2 and matching_number

etc..

not exactly what you asked for with all that maths but perhaps you could make use of this, if not no probs 

whoops error and I cant modify my post. corrected below:

Implied probability is (1/back_price)*100
(if you sum these it is the back book)

so top 2:
selections sorting order is defined by (1/back_price)*100 
and selections trigger expression match_index is between matching_number-1 and matching_number

top 3:
selections sorting order is defined by (1/back_price)*100 
and selections trigger expression match_index is between matching_number-2 and matching_number

Thanks for this - I can't get it to work properly (it returns (1/back_price)*100 for the first two selections), but the idea to provide what I think is 'finishes in the top two (if the favourite wins)' will provide a useful comparison vs. the actual probability calculation.

Having thought about the mechanics some more, and as it would take me a long time to try and work out how to set excel up correctly, I think my main question is whether MF and Excel could be combined to produce the variables I want / is what I want a feasible (set of) trigger request(s)?