can one large pdf be split into a packaged pdf?

can one large pdf be split into a package without having to extract pages then merged back together?

i have been scanning documents and some have been over 400 pages.

i have been creating seperate pdf's for each appendix/section then merging them into a packaged pdf to find each appendix easier.

but it is a bit time consuming to look at the 400+ pages then removing each appendix.

so i was wonder if it is possible to just find where all the appendixes start and have them put into package without need to extract each appendix one at a time.