Filling Multiple PDFs with Single Data Source

There is no efficient way to automatically link PDFs.  Not that it can't be done, but it's difficult and clunky.  However, there are multiple ways to transfer data between PDF files.

Here are 3. 

1) You'll find a tool here that copies form field data from one PDF to another.  It's not free. 

   https://www.pdfscripting.com/public/Copy-Form-Data-Between-PDFs-Description.cfm 

2) Write a custom tool as Try67 suggest.  Only I'd set it up to push data to the other forms from a toolbar button

3) Here is a simple manual solution if you have Acrobat Pro.  Export the data from one PDF and import it into another using the Data Import/Export options on the "More" menu in Prepare Form mode.

Yes, but it's tricky to implement, and will require installing a script on the local machine of each user who will be using it. Also, you will need to define when the values should update: Each time you change them in the "master" file? When you save it? When you close it? When you open one of the dependent files? etc.