How indicate conditional required field in editable table?

In a form indicating which fields are required are often indicated by an asterisk (*). We have an editable table and I indicate a required column with aesthetics in the title of the column.

The problem appears when initially no columns are required. But if the user fills one of the fields in the row, the next field in this row becomes mandatory and will not pass validation when the user will save the form. How to help the user and identify conditionally required fields?