I have a data table where the same samples were measured multiple times (see example below). The samples are separated by their identifier.

I want my script to be able to perform the same set of calculations on each sample so I can determine control limits and make a control chart for A, B, C, etc. I do not know the identifier of each sample. I already have a script that can do my calculations and make the charts for me, it just cannot do separate calculations for each identifier.
My initial through was to use some kind of loop to do this. I have a script that returns each unique identifier in a list and gives me the number of unique identifiers as a set up for the loop.
Identifiers = Column( "Identifier") << GetAsMatrix();
Identifiers set = Associative Array( Identifiers);
Unique Identifiers = Identifiers set << Get Keys;
nUnique Identifiers = N Items (Unique Identifiers);
I just can't seem to get a loop to work though. Is there a better way to do this? Or could someone show me how to do the loop?
I am using JMP 10.
Thank you!