How can I combine two or more folders into one AFP or SMB network share in OS X 10.11?
A new folder could be created 'Folder' (with Folder A/Folder B hidden by adding '.' before the folder names). In that new folder 'Folder', links to each of the files could be created. When folders are found in '.Folder A' or '.Folder B' a new folder and path is created in Folder.

A script could go through and first create the folders in 'Folder'. The script would then go through and create links to each of the files.

This is hokey as heck, but may work (for Macs and linux machines).
Each of these steps is a single find command (or a find command calling another script).

That's a non-eligant but simple solution. If you'd like me to write/test the two commands I will.