So far, I have this:
grep -B 36 'pattern1' Mapper.1.Configuration.MapRules | grep "pattern2" | cut -d'"' -f2
which give me a new-line delimited list of values that I need. I could put this into a file and then do a find and replace of all new-lines with commas.
But I'm guessing (nay, hoping!) there's a way to do this on the command line?