Are you trying to achieve this in a bar chart? Sub totals are not available in Sense yet but you have work around and can be done using the script.
In the image below, the aggregated values A-E and F-L are displayed to the bottom of the chart as you needed.
So follow this:
load * inline [
Mapping load * inline [
Load rowno() as Counter,*,
ApplyMap('Mapp', Dim) as Cat
load rowno() as Counter,Cat as Dim, Sum(Value) as Value
Resident xData group by Cat;
drop table data;
Sort the visualization by Counter
Thanks and Regards,