Hi brin,
Thank you, this is the natural/lilypond way of what I was thinking using the text editor. Good trick! not only for tempo changes, as you said!you can also do this using LilyPond's built-in tag system <https://lilypond.org/doc/v2.26/Documentation/notation/different-editions-from-one-source#using-tags>. You could thus create a #'part tag and do something like this:
Juan
