In a DTL to transform from HL7v2 to FHIR; select the code for the attending provider within a for each statement
<foreach property='source.AttendingClinicians()' key='st' >
<if condition='source.AttendingClinicians.(st).Code'=""' >
<true>
<if condition='..In(source.AttendingClinicians.(st).IdentifierTypeCode ,"NPI","PNPI")' >