Word Book Breakdown

This is for Microsoft word 2012 (not compatible programs accepted) EXPERTS only who understand how to work with making Word into book files. THE project: Break apart my 1 book into 5 books. I used to have my books in 5 parts, but have since combined them into 1 book, but they are still in 5 very easy to see sections. So... I just want them broken back into their separate books, but to ensure that all the pages, headings etc are correct. I am using the full book now as I have only been editing that one recently. I do NOT want to tell you what to do or what should be obvious. So do not ask to do this project if it isn't very clear to you what I am doing.