Work with variable font search paths.
Open the Fixups Window
Create a new Fixup
Give the fixup a name
Click "Additional search path - Choose" in order to create a variable.
Create the variable
Enter a useful path, e.g. to your desktop folder, so that you will be able to add a folder name.
Save the fixup
The new fixup shows up in the fixup list
If you now execute the new fixup a dialog pops up that lets you modify the search path for fonts