How to group multiple orders lists into one 'picking list' with items summary

Hello everybody!
I’m developing an app to receive three orders weekly. I have 90% of the app ready, but I am not managing to generate a report containing a picking list that sums products of all order lists together. Any idea how to achieve this?

You want to generate some “Grouping” inside the report without needing an extra table?
You need to nest start: expressions.

https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/PAGE-BREAKS-IN-PDFS/m-p/460458/highlight/true#M181321

Almost there! I need something like this:

ORDER 1:

QUANTITY PRODUCT
1 PROD-A
4 PROD-B
2 PROD-C

ORDER 2:

QUANTITY PRODUCT
3 PROD-A
5 PROD-B
10 PROD-C

I need to make this list:

PICKING LIST: (order 1 + order 2)

QUANTITY PRODUCT
4 PROD-A
9 PROD-B
12 PROD-C

You can use as much groups as you want