You should construct your model this way
Acct#Choice Group'A' header record 'F' record 'Y' optional record'B record'Z'record
The F record should be a complex type that repeats an unlimited # of tim ...
this is the structure of the input:
- first line is the header (record "A")
- detail contains 1..* line items (record "F") and 1..* additional Record "Y"
- summary rec ...