Measure width based on text, not notes

Measure width automatically adjusts based on the notes. If you have a lot of 16 notes, you'll have a wide measure, but if you have a whole note, it will be narrow. I would like the measure to auto-size based on the text attached to the notes. For instance I want to write something over that whole note, and that text should be bounded within the measure.

Can individual measure widths be adjusted? It seems to be all or nothing.