Welcome to the Dataiku community.
From your description, I’m not completely clear that I understand your use case.
That said I’m wondering if the visual recipe fold and unfold function might be of help to you. These are sort of like pivot and up pivot functions you might see elsewhere.
If this clue does not help. I’d invite you to share a specific example of some sample data showing what the data looks like before and after the transformation you are trying to achieve.