Never worked anything out as far as I recall. May have tried to use MSRP once or twice but generally it was easier to to use the next process.
Mostly the onwards processes I have been involved with were run on Unix systems via a script and the easiest solution was simply to write a line in the script that deleted the last line of the report. Perhaps a check to make sure that it was pretty much the line expected as well sometimes!!
If there is a hidden parameter somewhere which coould be said to be reliable is would be good to know.