There is another way to organize pages and it is my favourite so far because it scales well with very long complex “poly-hierarchies”:
You can write indexes like the following where you want:
- [[Index]]
- [[Foo parent]]
- [[ Foo child]]
- [[Bar parent]]
- [[Bar child]]
Then when you are on a page and you want to see where it is in one or more indexes, use
{{query (and <%current page%> [[Index]])}}
You will be able to browse the hierarchy without leaving the page.
You can create a macro with it and a custom command, so that you can just type /Index at the top of a page to add it.
P.S. you can use my minimal style for queries to make the indexes look more native: