Custom validation using setError for dynamic form with + and - button to add three columns in a row and delete as well

[niteshk88]

How to set a custom validation for the dynamic form where the rule will be that if neither of the three column is filled, on click of + button to add new row, an error message should be shown to fill at least one of column in order to add row. My problem is the error message shows for all the rows despite it is valid or invalid and not only for the last row if it is invalid.