Smart Bitrix filter for the entire catalog, how to do it?

Question

1C-Bitrix

Hello comrades!
There was an idea to make a filter on the site that will filter bypassing the sections.
There is such a structure:
0. /catalog/ - root (filter gets all available properties, but does not display elements)
1. /catalog/zhelezo/ - section with subsections 5 or more (filter gets all available properties, but does not display elements)
2 ./catalog/zhelezo/platy/ - section with elements (all elements in this section are filtered)
The filter is available at all nesting levels!
How can I make it show all available elements from subsections after applying a filter inside the /catalog/zhelezo/ or /catalog/ section ?
Maybe I didn't search well, don't throw stones please!
Tell me where to dig, maybe give some example or advice.
ps I'm
using a complex component...
pps

I want to customize smart.filter so that I can filter/display elements being, say, in Section 1 or Under 2, it doesn't matter.
Being in the root of the directory, we can filter and display all available elements, let's say with the color "Black", Being in Section 1, we can display all elements with the color "Black" available only within its subsections.

Answer 1

I understand you correctly.
Do you want to display a list of all elements from the infoblock and sort them? And by what field, sorting is needed?