No unique identifier in FCC

Hi Experts,

We have a requirement in SAP PI (7.31) where the flat file is picked from source and sent to Target.

FCC is used for conversion in the sender channel.

Incoming files has two header, with each header multiple line items under that.

The line item has dynamic value after "D".

Example :

H1

D12

D25

T1

H2

D45

D87

T2

Need inputs on how to proceed in case of no unique identifiers in FCC.

Thanks,

Pavi