Pivot table - sum a number of group

[Cferron]

I'm not sure if this is possible in an Excel pivot table.

I'd like the information to get updated if the pivot table changes.

I have a pivot table placed from A to E (data are in another tab).
Column C & D are basically grouped using the pivot table.

Instead of the number of occurence of a same time, I'd like to know how many items are part of a group. See example below in the screen shot.

Is this possible? If so how?

Thanks

Claude