Designing an interface for document slicing/splitting

I am given a PDF that consists of a series of scans, all concatenated together in a single file. I'd now like to allow the user to split said document into multiple documents for easy retriveal. It can easily happen that a connected topic spans multiple pages in the scan, and these pages should be exported together into a single file. What could be a sensible interface to allow the user to choose which pages should stay together and be extracted/exported into a single document?

I have considered a list of checkboxes (one for every page), where you'd select page numbers that stay together and then click an "Export" button, which would remove these pages from the list view and export them into a single file, but I'm unsure if that's a sensible design decision (since I have next to no experience in UX).