Sorry for commenting after you already found a solution. I too am curious as to how you solved it.

I like BioLion's solution, except I would add regular expressions to definitively identify which of the 3 log lines you have. In other words, make sure that you are grouping the correct 3 lines together.

Since this is a log file, and log files are commonly rotated and/or truncated, you cannot be sure that the first line in your log file is the first line in a 3-line group. It is safer to not make that assumption.