Group By on two levels

What if I wanted the number of files not in a separate column, but behind the ‘name’ of the website between brackets?

Network Website
A 1 (1)
_ 2 (1)
B 3 (2)

I’ve tried to compile it as

rows.Web + "(" + map(rows, (r) => length(r.rows)) + ")" AS Website

but that doesn’t work… I then get a sequence of Websites and a sequence of numbers…

If I’d know how the data is fetched and processed, perhaps I could figure it out myself… But unfortunately I can’t seem to find the inner workings of these queries.

Thanks in advance for the help!