I have to open the ssd version of kontakt, preferably in 32 out version (to have more outputs).
I load a kit,
go to the reaper's track FX chain edit window, right click on the kontakt instance and "auto create outputs automatically" or something like that.
It creates a lot of reaper tracks, where are routed kontakt outputs.
Then, inside kontatk, I go in the mixer, and at first every kontakt track (so every tom/snare/cymbal instance) is routed to "output #1 / output #2" (these are L and R channels of that kit part)
(they have some names but don't use them).
Then, I let 1/2 for the first track (obviously the kick). Use 3/4 for the next part, 5/6 etc.
It should work; and if you routed every kit part correctly, tracks will be fed by the correct sounds. The first reaper track will be the kick, the following the others, etc. Now rename the tracks, and you're done.