Rekordbox STEMS with the idea to use deck 3 or deck 4

Hi,

My Dream, Rekordbox to do that :

https://www.youtube.com/watch?v=W-OlFTWoxfQ

(Done manually with VDJ stems exported in CDJ format, export CDJ stems function of Virtual Dj 2023)

But how i make Deck 3 or 4, midi slave ?

please Pioneer see video and take the suggestion :)