Load section & page data from separate file?

I have a client for whom I built a custom FAQ section (thumbnails, animations, etc) and included it in the Default Product layout (product.json) and it’s own custom FAQ page template (page.faq.json). He would like edits he makes on one to be replicated on the other, but naturally they save any entered data to their own files. Is there a way to have the default product and page template write to- and read from a separate file so the data between them can stay in sync? A “single source of truth” option?