Do not want to concatenate data in a loop

I have seen examples of loop workflows for people who want to read several files and combine (concatenate) the data from all of them. In my case, I want to read the rows in each CSV file, add some new columns to row, and then write the file in a subdirectory – one at a time. But instead when looping, KNIME combines all of the rows from all the files into one output file.

What is the setting to prevent concatenation?