I'm working on a story in which has multiple chapters using the
memoir class. However, within this single book, I want to separate the chapters into three groups (much like The Lord of the Rings books have two "books"). Ideally, this would print a separation page labeled "Book I", "Book II", "Book III", etc. and group the chapters in the table of contents under their appropriate books. But it's important that the chapter numbers increment continuously, so if chapter 8 ends Book I, then the beginning of Book II would be chapter 9.
Note: I'm working in ShareLatex for this.
How would one accomplish this?