[Wanilton]

The best way is split movies 4k in a distinct folder, and use smartplaylist to filter based on the path. You need create 2 smartplaylist, one for regular resolution, other for 4k, use replace function to change Movies default item with your smartplaylist, and create one second item to the other item.

Here one video in Portuguese using MQ9, but it´s very similar, follow the steps...