File to IDoc Mapping Issue

Hello Folks,

Please find my input/output structures...It has 1 header and multiple Items. and I dont get any key field on Item values.

How can I achieve the target structure as below; Please guide me!

Input Structure: ( file)

AAA,BBB,CCC (Header Details)

123,456,789 (Item Details)

456,789,123 (Item Details)

789,123,456 (Item Details)

Output Structure:

ITEM ---0 to Unbounded

ITEM_GROUP ---0 to Unbounded

NAME:AAA

VALUE 123

NAME:BBB

VALUE 456

NAME:BBB

VALUE 789 . ( for 1st line Item details as first Item group)

NAME:AAA

VALUE 456

NAME:BBB

VALUE 789

NAME:BBB

VALUE 123 .( for 2nd line Item details as 2nd Item group)

NAME:AAA

VALUE 789

NAME:BBB

VALUE 123

NAME:BBB

VALUE 123 .( for 1st 3rd Item details as 3rd Item group)