If you stick 20 pages in the adf, you get one 20 page job, or 20 1 page jobs. It can't possibly know any more than that, it has no AI, it does not in any way interpret what is on the pages, its just a printer.
Now, if you are scanning the job in sections as separate scans and still getting one job in the shared folder, that would not be the default way it behaves, that means someone at your site told the printer to always add to the existing file, instead of creating a new file, so if that is your scenario you are going to have to provide more information, specifically:
1. What type of scan
2. What firmware is on the printer
3. What file type you are using