Kontrol S2 as main controller and Xone:K2 for effects - how to setup?

Dear all,

I am really desperate because I seem to not find any answer to this problem of mine and it is driving me nuts because I suppose this is a very easy problem to solve if you know how to do it.

So here it goes:
I am having trouble running my Xone:K2 in combination with my Traktor Kontrol S2 in Traktor Pro. I would like to run the S2 as main controller, and "outsource" the FX functionalities to the K2. However, I am not able to set both controllers active at the same time. I can either choose the K2 or the S2 as my main device in the audio setup controls in Traktor (both being connected to my Macbook via USB).

I would really appreciate some support here as I cannot find any setup manual or guide online.

Thanks a lot in advance!

I don't have a k2 but why do you want to use both soundcards? You cant' and it's not necessary to do what you want here anyway. Your main soundcard is your s2's, the k2 will be a midi controller used without its soundcard (if you need to deactivate the k2's soundcard for it to be used a a plain midi controller, please refer to your manual, I don't have the info).
You simply need to create a midi device and midi mapping for your k2 in the controller manager for the functions you want it to have. Makes sense? Of course here I assumed you only use two decks for audio.

Like Yul said, you only need the S2 set up as your audio interface, everything else is handled internally via MIDI Mapping.