Sum Values Based On Department.

From the example data of my previous post i would like to continue further to sum all the amounts based on department.My requirement is to sum the amounts in the next column down the department column. i had splitted the actual data into two categories based on departments "CNN" & "CNN-IN".

I had many departments like this in my data which i want to display them in different categories based on departments and the sum of the amounts in the next below cell of department. i got an idea on this that solution can be achieved if i apply Filters & Auto filter.But i m not perfect with the code and syntax.