The RMX-1000 by Roland possible to use it on my Prime 4?

Are you using a translator to read my post? :face_with_monocle:

Take a look at my setup Show your home DJ booth (Part 1) - #392 by Wyley1

I can sample from and add external fx to any source plugged into my mixer fully synced and quantized. I would get more out of using the rmx 1000 with my setup than you would get by adding it to your prime4.

SlayForMoney summed up my comment for you.