Hi Siva,
Respect your question... I think, is depend of your scenario.
i.e. If you check the GOS Services in "Attachment List" option, you check all documents attached in a list inside a new screen for every PO number.
So, for you module pool program, you can have some similar if the user will load several files, BUT DON'T FORGET that all files will exist in SAP, and they files will be exist in SRGBTBREL Table, you will need store the files on this table using the funtion in Step 2 mentioned.
Regards,