Dutching back in 2, 3 or 4 favorites

Hi
in test mode try condition blocks like this:
OR
  selections rank is between 1 and 2
  and selections trigger expression r_3_back_price-r_1_back_price is greater than MBP
OR
  selections rank is between 1 and 3
  and selections trigger expression r_4_back_price-r_1_back_price is greater than MBP
OR
  selections rank is between 1 and 4
  and selections trigger expression r_5_back_price-r_1_back_price is greater than MBP

Thanks MarkV

For testing, I created 3 blocks with the Alert command action:

BLOCk1:
selections rank is between 1 and 2
AND
selections trigger expression r_3_back_price-r_1_back_price is greater than MBP

BLOCK2:
selections rank is between 1 and 3
AND
selections trigger expression r_4_back_price-r_1_back_price is greater than MBP

BLOCK3:
selections rank is between 1 and 4
AND
selections trigger expression r_5_back_price-r_1_back_price is greater than MBP

MBP = 4.9

Example 1:
Greyhound racing (G1, G2 ... G6), we have the following back_prices, when monitoring begins:
G1 = 2, G2 = 4, G3 = 5, G4 = 7, G5 = 10, G6 = 15
--> result: BLOCK2 and BLOCK3 are executed and should be only BLOCK2.

Example 2:
Greyhound racing (G1, G2 ... G6), we have the following back_prices, when monitoring begins:
G1 = 2, G2 = 4, G3 = 8, G4 = 12, G5 = 14, G6 = 15
--> result: BLOCK1, BLOCK2 and BLOCK3 are executed and should be only BLOCK1.

Summarizing: the trigger has to test the conditions in the sequence and, finding a true one, do not test the following ones.
In my trigger, I will not do 3 blocks; I need the condition test to return a unique selection of favorites: G1, G2 or G1, G2, G3 or G1, G2, G3, G4 so that the trigger dutching using only one of these selections.

If it was in a BASIC type language, it would be easy because I would use IF, THEN, ELSE ... I do not know yet if the MFP supports this type of programming.

Thanks in advance for the next help.

The programming logic would be:

r_5_back_price - r_1_back_price > MBP?
FALSE -> does not execute trigger (not met)
TRUE --> r_4_back_price - r_1_back_price> MBP?
               FALSE -> selection = F1, F2, F3, F4 -> executes the trigger
               TRUE --> r_3_back_price - r_1_back_price> MBP?
                              FALSE -> selection = F1, F2, F3 -> executes the trigger
                              TRUE --> select = F1, F2 -> executes the trigger

Thanks MARKv

I was testing using a variable that would change the value before the dutch of each trigger. This variable NUMBER OF RUNS performs better the function. 
I will test in the next races. 
The problem is whether the MFP starts testing the conditions of the first block and then tests the conditions of the second and after third.
If the MFP tests all at the same time, it can first execute the 3rd trigger, when the first one should be executed.

Example: back prices (favorites in order) -> F1=2, F2=4, F3=8, F4=12, F5=14, F6=15 and MBP = 5.99

If all blocks are executed at the same time, all will have their conditions = TRUE. 
If the MFP first executes the 3rd trigger (or MFP will always run, first, the 1st block?), it will be wrong, as it would have to execute only the 1st trigger (dutch in favorites 1 and 2).
Therefore, the ideal would be some command that forces the execution, FIRST, of the 1st block and, only after, the 2nd and, after, the 3rd.
As the flowchart below:

r_3_back_price - r_1_back_price > MBP?
TRUE ---> Selection's Rank is between 1 and 2 --> run Dutch Back trigger
FALSE --> r_4_back_price - r_1_back_price> MBP?
          TRUE ---> Selection's Rank is between 1 and 3 --> run Dutch Back trigger
          FALSE --> r_5_back_price - r_1_back_price> MBP?
                    TRUE ---> Selection's Rank is between 1 and 4 --> run Dutch Back trigger
                    FALSE --> condition not yet achieved (does not trigger yet)

Of course there is another condition that keeps testing the above conditions until just before the market closes (variable OFF)