Hi Srikanth,
it will be more manual work if you don't want to use routine BADI, what you need to do in the 2nd load is you need to filter on the ID so that only valid ID in BPC will be updated.
maybe you can ask BW guys to create a new attribute for you in BW in the 2nd info object, then you can just filter that attribute in BPC instead of selecting the IDs yourself.
Andy