Sum Cumulative data in SubReport

[DocBrown]

I'm trying to generate a cumulative report for some demographic data. And I'm
Grouping the data.
The relevant fields of the tables are:

Events Table: Eventid, ProgramArea, ProgramName, (other data)

ZipData Table: Zipid, Eventid, Zipcode, count

Example Events data:
1, Program 1, Name 1
2, Program 2, Name 3
3, Program 2, Name 4
4, Program 1, Name 2

Example Zip Data:
1, 1, 90001, 5
2, 1, 90002, 3
3, 2, 90001, 4
4, 2, 90003, 2
5, 3, 90002, 4
6, 3, 90003, 6
7, 4, 90001, 5
8, 4, 90003, 7

The report is grouped on ProgramArea. The report should look like:
----------
Program 1

( other data cumulative here)

Zip Data:
90001 10 <- sum of Zip recs 1 & 7
90002 3
90003 7
----------
Program 2

( other data cumulative here)

Zip Data:
90001 4
90002 4
90003 8 <- Sum of zip recs 4 & 6
----------

The cumulative (other Data) is working. I put the sums in the Group Header
section of the report.

On another report I have the zip data displayed by EventID with a sub report
Linked on the EventID.

What is the approach to do this? When I try to put the zipData in a sub
report, only the first record in each group is displayed and summed.

Thanks in advance for any help.

 

[DocBrown]

I think I figured it out....

I created a sub report with a parameter query that got the value from the
ProgramArea_box in the group header of the main report.:
[Reports]![Programs Activities Cumulative]![ProgramArea_Box]

I then grouped the subreport on Zipcode.