What exactly is the "custom way" you are talking about?
In the queries our programming options are rather limited. We can add some code in AT SELECTION SCREEN and use CHECK in the record processing node to skip some records, for example. There is really no place where you can just take a field from the selection screen and manipulate before data is selected.
If you can clarify what you are doing exactly there might be some workaround, but otherwise I'm afraid you'd need a custom program.