How to Aggregate Nested Iterator Results to Single Program-Level Value?

Hi Fusion Community!

Wondering if anyone can help with the following challenge?

Issue: I'm building a Fusion scenario to calculate a program-level metric that requires aggregating data across multiple nested iterators: Program → Projects → Tasks → Assignments.

Current Flow:

1. Get Program details
2. Iterator: Loop through all Projects under Program
3. Iterator: Loop through all Tasks per Project
4. Iterator: Loop through all Assignments per Task
5. Calculate cost per assignment: (User Cost Rate * Planned Hours) / 60
6. PROBLEM: Need to sum ALL assignment costs into ONE program-level value

Expected Result: One bundle with total cost = sum of all assignments across all tasks across all projects

Actual Result: Multiple bundles/operations, each with a subset of the total

Question: How do I aggregate across multiple nested iterators to produce a single output value at the program level? Is there a specific aggregator configuration or module placement that works for this nested scenario?

Any guidance is appreciated!

Thanks!
Nick