concatenating PDF files

Hi,

   I need to call the Adobe form Function Module inside a loop. So I want to concatenate all PDF outputs in a Single PDF file. Here is my Function call code

call function iv_fm_name

     exporting

       /1bcdwb/docparams  = is_docparams

        bil_prt_com        = is_interface

importing

       /1bcdwb/formoutput = es_formoutput

     exceptions

       usage_error        = 1

       system_error       = 2

       internal_error     = 3

       others             = 4.

Any suggestions Please to get this done in my ABAP print Progam.

THanks

Swarna....