Suggestion how to localize templates XAML

Hi,

my application is composed by a main window which loads in its client area different XAML for different customers.
The directory structure of the program is:

MyProgram
     |- Templates
              |- Customer A
              |- Customer B

in the Customer folders there is the XAML file to load dynamically.
Now, which is the best way to localize the XAML without to touch the main application?

I don't want to store the strings into the application resource file because I don't want to rebuild it every time I have to made a change to a customer GUI.

Thanks in advance for the suggestions!

Daniele.