Hi Sumeeth,
The F. Sel group comes under the F. Sel Key. The F. Sel Key is linked with the document type. So, depending upon your document type of PR, you can see the F. Sel Key to be customised. Then you select that F. Sel Key and under that you need to check your F. Sel Group. Field Selection Groups are created by grouping fields having common interest/property/use. There is no logic I think.
Regards,
Vishram
