Page groups can help you organize and view your pages.
You can create page groups and subgroups within page groups. For example, if you have a job for a book that has 500 pages, you can create a page group for the table of contents, a page group for each chapter, and a subgroup under each chapter for appendixes. You can then choose to view pages in a particular page group or subgroup.
You can:
Pages belonging to a deleted page group remain in the Jobs area and are moved to the Unfiled page group.