Hi @reuben 
If I understand you correctly, are you trying to merge all of your items into a single row grouped by order? If so, check this post by another Parabola user.
The “Insert Text Column” step can be used to format each item as a JSON object in a single row. The “Merge duplicate rows” step can be used to merge the items together and group them by a unique identifier.
In your case, you may be able to use a unique Order Id or Order Name to group your items. Your final JSON might look like this:
Order data
Order data
"items": [
{Merged Items Column}
]
Order data