EAN lookup in bulk

Hi, is there any way we can do a bulk check of EAN codes to see which ASINs are already existing on amazon, and which are new? I know there are 3rd party tools to do this, but surely there must be some way to do this in Seller Central or using Amazon approved tools?

Background is we have a lot of new ASINs coming in which occasionally has global overlap. We don’t want to spend time filling out all the required information in the bulk listing excel sheet, when the listing is already live on Amazon. Checking one by one from the Add Products page is not an option.

Please if anyone have tricks, share. I heard someone was using the List Loader to do this by syncing it with AWS to lookup the EANs directly in the excel sheet, but I have no clue how to do this.

Any help appreciated.