Hello @Andrew_Duncan,
is this what you are looking for?
- How to `show` an outline at each level 1 heading for all its child headings? - #3 by quachpas
- How can I create "sub-outlines" with restricted scopes? - #4 by Tinger
Is the part also a heading? In which case, you should write it as level 1 heading, e.g., = Part 1, then your chapter is == Chapter 1.