Variable External File Names (or alternative)

Is there a way to have an undetermined number of external file references? It seems that you must declare the external files to be used explicitly in the story file, but I am attempting to figure out a way to add data to the game in the form of data “mods” that don’t require the story file to know about them in advance. Is this possible in any way?

I tried the following, expecting it to not work, but it was worth a shot:

FileText is a text that varies. FileText is "placeholder".
File of Variable Name is called "[FileText]".

Other logic foo:
       now FileText is "otherName";
       etc. foo;

Of course, this syntax doesn’t work here, so…

Is there a way to do what I’m trying to do here? Is there some other method to make it possible for a story coded as a “framework” that can read modular data added from “random” external files?

You’ll have to do it with some I6 code. As an example, check out my Ultra Undo extension.