Arcy
Strummin' in the Rain
You can use a PDF editor to split PDF files or merge them. Search on "split PDF file free windows" (or Mac or whatever) and you should get several options.How do you split them all out so they get arranged in alphabetical order as single songs rather than 50 in one Book in one file?
I use PDFSam Basic (free from http://pdfsam.com for Windows/Mac/Linux) to merge multiple song PDFs into a single setlist. It worked well and simply enough for my needs that I didn't look any farther.
Splitting your PDF may be more complicated than merging if the individual songs aren't separated in a way the tool can detect (one song per page, bookmarked, etc.) You may need to do some manual extraction, extract and then re-merge, or such.
Commercial PDF editors can do a more and will be a lot more visual if that's more your comfort zone.