Sorry I misread what you said. I thought you meant 2 files for the same extension.
In Ruby (because it is a dynamic language) we can open an object multiple times, in multiple files, and modify the object. Modules and Classes are objects in Ruby, and can be reopened using the interpretive module and class blocks.
BUT NO each extension must have it’s own registrar file in the "Plugins" folder, and it’s OWN subfolder that is the same name as the registrar file.
The example I show above is for one extension that can draw two kinds of boxes.