When data is loaded from multiple files using Data Management in FCCS, how to know the source

Summary:

Customer is loading the data for same entity through multiple files (First file is loaded in Replace mode, while the second and third in Accumulate mode). The POV for these lines can be exactly the same but the sources for these three files is different. Customer wants to know the information about which line is loaded from which file.

Content (please ensure you mask any confidential information):

File 1:

Entity 1->Account1->ICP2->Amount

Entity 2->Account1->ICP3->Amount

Entity 3->Account1->ICP1->Amount

File2: (loaded in Accumulate mode)

Entity 3->Account1->ICP1->Amount