Column Group with variable Column Count

[#1]

Query_DT << GROUP COLUMNS("WEEKS",COLUMN(12),75);
COLGRP = Query_DT << GET COLUMN GROUP ("WEEKS");

Query_Stack = Query_DT << STACK(columns(COLGRP),
	Source Label Column( "Label" ),
	Stacked Data Column( "Data" )
);

I need to group columns to create a stacked table..  the problem is that the number of columns can vary.  This code works fine, except in the Group Columns function I need the 75 to be a variable count of columns from that same starting position.

I can't seem to find exactly what I'm looking for in either the Scripting Library or the search here.  Any ideas?

[#2 · Accepted solution]

What is the number 75 based on?

Script below will group columns starting from start_idx column to the last column

Names Default To Here(1);
dt = Open("$SAMPLE_DATA/Big Class.jmp");
start_idx = 4;
dt << Group Columns(Column(start_idx), N Cols(dt) - start_idx + 1);

[#3]

75 is the number of columns to include in the group.  Your code worked perfectly.  Thank you!