Here below is a data table:

The task is to group by Dept, and concatenate the names within the same group into the same row:

=spl("=E(?1).group(Dept;~.(Name).concat@c():Name)",A1:B12)

esProc Desktop and Excel Processing
11.11 Group by interval of data values
11.13 Auto-aggregating in the case of multiple columns - unfixed number