Is there a way to prepend group headers?

[Charles]

Given multiple groupings, I would like to prepend {groupField: groupValue ->} to each child grouping.

For example:

Group Result:
Supplier ID: 1
Supplier ID: 1 -> Category: Beverages
Supplier ID: 1 -> Category: Beverages -> Name: Chai

How can I retrieve the child group's parent groups, so I can prepend them to the child group's header template?

Thanks!