You can use Soda PDF to split up the document. It wonât split the contents within a page, but say you have a 30 page document. If you want to make 6 documents of 5 pages it can easily accomplish this. There is both a full app and a quick online tool.
I can't tell your from your neighbor, and I can't tell my own friend from another person's friend, therefore you might end up with a PDF document you can't use. It is a good idea to print out and keep a few copies, some for backup and some for safe storage. Once you get used to this, you can open up your documents in different apps, and you won't have to worry about duplicates anymore.