What I'm thinking you could do would be to somehow number each login time and save it as an expression. So for user A, 10:52:03, 09:33:21, 10:30:47, 10:01:53, and 10:12:19 would all be "Login1" and 14:22.31 would be "Login2." You then would have this "LoginNumber" expression as a row heading...