Setting default heading levels on the navigation plane

[MattRNR]

G’day word forum
Quick question (I hope), is there a way to set as a default the number of heading levels visible in the Navigation Pane? I have a document I use daily containing all of my current projects, my calendar, next actions, delegated tasks, etc. I find given the number of sub-headings and lists on this document it can be cumbersome to navigate with all of the subheadings visible all the time and it would be substantially easier to have just 1 or 2 on opening and then expand any 3rd or 4th levels or more manually using the arrows to the left of each heading.
I’ve been looking around on the net but I can’t seem to find any solution, is it possible to set a heading level by default, perhaps using a macro or something if need be?
Regards
MattRNR