Multi list in same paragraph numbering

I can almost get there, but there is a bug in InDesign’s numbering feature, which I will explain.

By assigning a numbering level of 1 to the headings and a level of 2 to the numbered paragraphs I can get the numbering I want for the numbered paragraphs, but that means I have to also apply numbering to the headers. The number field in the second image includes a reference to the number of the current level 1 list.

You might think it would be easy to just not enter numbering options for the headings. Format them as a level 1 numbered paragraph but leave the Number field blank. Unfortunately, without having a number included in the text InDesign kind of forgets what it is supposed to do.

If I leave the Number field blank for the headings…

The numbers for the rest of the text break.

So there’s no solution that get the numbers right for all the text, right? Well, maybe. But If I create a character style that is practically invisible…

It works!

So how did I make the number invisible? The point size is 0.1 pt, horizontal scaling is 1%, and there is no fill colour. Technically the numbers are there, but they don’t print and take up no space.

I don't think that numbering can be done in any way but manual entry. (I'm sure some kind of a script could be written to apply the numbers, but it would not be automatic and any editing would require the script to be run again.)

The only thing I know of that can trigger a numbering reset is a change in the 'parent' number. If there's any way to have some second paragraph style trigger the change... I am not sure how it would work or how to make it consistent.