Maybe I'm misunderstanding the idea of married segments. I took it to mean that, for a given city pair, the R value would be the minimum across all the passenger's flights between that city pair. So, in this example, the R value shown for both 859 and 837 would be 0, since the R value for 859 is 0.

Why then, when the itin is booked as a one way ORD-NRT, does it show 859: R=0 and 837: R=9? The two flights are still shown as a connection; the user isn't doing a multi destination search.