If i understand your problem correctly, you could try to match the "id" of the object in the query. In the database retrieve you can match on the attribute id. Example constraint: "[id = $iteratorObject]"
Made an error in the flow of the programme. have corrected it in my OP.
The CSV file can contain incomplete entries, but all data should be imported. Therefore we have to define multiple Interface Definitions. Hence a list of those Definitions (being 1 to more, depending on the import) to process that CSV file and get all entries imported.
We do not want to retrieve the iterator object (Interface Definition) but the Queue Definition. It can only be procesed once officially (attribute Process = true), but in this loop we may need it multiple times, as the Queue Definition contains the file name to be processed.
The problem is you cannot use the same object name in Mendix when retrieving the same object, while that should not be the problem.