How to merge PDF bookmarks when merging PDF documents?

Q: Basically we need to merge multiple pdf documents together and merge
bookmarks from the documents. I can see where merging documents is no
problem but do not see a clear way to do the bookmarks?
To merge bookmarks from multiple documents you would need to iterate
through bookmark items in the source document and then recreate the
same items in the destination PDF document. Bookmark sample project,
which is part of PDFNet SDK
( illustrates how
you could iterate over existing PDF bookmarks as well as how to create
new Bookmarks.