1: 2: 3: 4:
SELECT t1.* FROM tblEvents t1 INNER JOIN tblEvents t2 ON t1.EventID <> t2.EventID AND t1.EventTime = t2.EventTime AND (t1.Cust1 = t2.Cust1 OR t1.Cust1 = t2.Cust2 OR t1.Cust2 = t2.Cust1 OR t2.Cust1 = t2.Cust2)