How do make subsections based on block depth?

Using the following setup results in a flat structure in the document, where each section is just incremented for each block, i.e. Section 1, Section 2, Section 3.

How do I set it up, so the structure is based on the highest level block and each block inside that is assigned a subsection?

Say I have two blocks at the highest level, i.e. Section 1 and Section 2. Both these blocks has 2 block inside them, so the structure should be:

Section 1

Section 1.1

Section 1.2

Section 1.2.1 (If there's an even deeper level)

Section 2

Section 2.1

Section 2.2