getting every nested rows from an executed report in a single API call

Hello,

We would like to get every nested rows from an executed report in a single API call. As you can see at the attached picture.
I need to import every "subrows" in one request.

1 . report/cleanup_result
2. report/exec_report
3. report_select_result_rows ({"tableIndex":0,"config":{"type":"range","data":{"from":0,"to":<row.count from exec report result>,"level":0}}})
4. And here I want to get all "subrows" for the "main" rows from above response. There are many "main" rows, not just one. (At my picture are 2 blue lines)

Also downloading each "subrows" in different requests is very slow..

With an ajax call we can get "subrows" in different requests (when I click on plus):
report/select_result_rows - params:{"tableIndex":0,"config":{"type":"row","data":{"rows":["2"],"level":0}}}

I need the same result/response as the above request produces, but for many "main" rows, not just for one from SDK.

Any idea how can we manage this?

Thx,
Attila