JSON:Array in a collection is simply a collection, so you could loop through the main collection, and access the fields using their corresponding field name.
For example:
Loop over collection -> have a calculation stage where you have the expression: [Collection.JSON:Array.FIELDNAME] and store the result to a data text item.
Or you could handle that part using code blocks, set the JSON collection as input with some filter criterias, and a filtered collection as output.