Write to a file from a Widget to be read by an Automation

I will start by saying that this may not be the best approach and I'm open to ideas. I was just trying to avoid writing a plug-in...

Concept:

  1. A user (role based access) be able to associate Sitewide User Roles with Applications in a manageable and editable list in a custom widget displayed on a custom page. (Probably something like key, pair)
  2. Have that page be site-wide and the list editable by users with the appropriate access.
  3. Have an automation triggered by user role activity execute its function dynamically based on the association of this list.

Self-justification for this path:

  1. Only have to have one automation for essentially the same action with different variables
  2. Configuration can be managed by non-coders/non-administrators

Stumbling block in researching feasibility:

How do I write to a file (in the CFS or really anywhere server side) from a widget to be read by the automation? I can find documentation on how to read files in both widget and automation contexts, but I've missed any reference to write/set functions.