Report group by nested?

Hello to everyone,
In the reports module is there the possibility to group (and have total) nested?
In my case, I create a report for Meetings module,
Main Group is assigned_user_id
I add a custom dropdown menu (argument)
and choose total (sum) for minutes and hours duration.

Now, I have a report that for each user, show all activities and sum the durations.

I would like a report that for each user, show all activities and generate make the sum of duration group by argument value
example

User 1
activity1 arg1 3h
activity2 arg1 2h
activity3 arg2 1h
activity4 arg2 7h
activity5 arg3 2h
TOTALS:
sum arg1: 5h
sum arg2; 8h
sum arg3: 2h

At the moment, my report result is similar then this:
User 1
activity1 arg1 3h
activity2 arg1 2h
activity3 arg2 1h
activity4 arg2 7h
activity5 arg3 2h
TOTALS:
sum: 15 h

Thank you so much for the help.
B.

With Reports (at least for me) it’s mostly a matter of trial-and-error, play with all the available options until you get something that works, or give up…

If all fails, you can try Google graphs, see here:

Google graphs can have a “table” format where they look like Reports essentially.