The $FileGroup function creates a group based on the text file. It expects a set of delimited values in the source file.
The function has following parameters:
$FileGroup(1,1,d:\data files\discounts.txt) - specifies 'discounts.txt' as data source and uses the first column.
$Group(1,2) - refers to the second column.
$FileGroup(1,1,d:\countries.txt,0,0,|) - the engine should use pipe as value separator for 'd:\countries.txt' file.