Share a mvn settings.xml across projects

I’ve followed the information on https://circleci.com/blog/optimizing-maven-builds-on-circleci/ about how to use a custom maven settings.xml for my project and have gotten it working. I have a number of projects that all should have the same settings.xml and I’m trying to figure out how to avoid duplicating that file in every one of my repos. It seems like my best bet might be a git submodule but wasn’t sure if there were any options that were more native to CircleCI. The other option I considered was an unlisted orb but I don’t like the idea that it is still available to people outside of my org even though it is unlisted. Am I missing something that would make this work?

Thanks for any ideas