Maybe code owners? I'm not sure if it'll do exactly what you want; but you can say that "such and such" files must be edited, or reviewed, by specific users.

Then, if someone opens a PR who isn't one of those people listed, it requires them to be a reviewer.

We use it for .editorconfig; specifically, we don't want a newcomer to come in, not like a style rule, and slip in a change.