you can't, really. and some of my favorite posters here, always show the telltale signs of reply to a digest message: dwayne and dennis. I like to read a thread, so i sort individual mail to the thread. But, alas, Dennis and Dwayne will never be in the thread due to the way a mail reader will sort based on the "in-reply-to" header in your email. So, sometimes, I miss their scintillating commentary until after I've read the thread. Or, I have to go rootin' 'round my email program for their nuggets and figure out where they belong, in terms of time sequence. Like how long did it take Dwayne to come up with a clever flame for the wojbot. ha ha.
these are sometimes important datapoints in my day.
so, i must go on, in spite of it all. it's the suckage, but they are the ones who know how best to manage their email, not me. it's the price a bitch has to pay for reading her buds. le sigh. :)