I was a heavy support of Leanbean back in the days, but I remember that we were told something along the lines of "it's not gonna happen, because it would make it even easier than it is today to run stuff between few players, rather than sharing it with many others. If you want this feature, just get all the people you regularly talk to in the same guild or secret society and you're gold".
Plus one for replaying group messages. I think it would be quite helpful.
