Pseudo code: If a.Event ID = b.Event ID { If a.FileName = b.FileName { If a.RR Security code = a.RR Security code FileName = FileName + '/' + b.FileName (e.g. if (a)FileName = 'ONE_ACE' and b.FileName = 'TWO_ACE', then FileName = 'ONE_ACE/TWO_ACE') Return nothing; Else Return data of row to be included in output file; } Else Return data of row to be included in output file; } Else Return data of row to be included in output file;