I hope I understood your inquiry correctly.
Is this what you're trying to achieve?:
(see attached image)
If so, as C4D can handle material stacking, one way to do it is by first defining the displacement, and then overriding the base material that uses displacement with the one that you need (in this case a leather material).
I'm including a sample scene file for you to experiment with. (please use an HDRI file of your own, as I'm not including this one due to file size)
I hope this helps.
Let me know the outcome.
Regards.