Until the arranger manufacturers standardize the codes for arranger operation, combining a Yamaha and a Korg (or really, any two at random) into one is an exercise in frustration. Sure, easy enough to have one do the style, and the other do the RH sounds, but the idea cries out for say the bass line from the Yamaha style, combined with the style guitar part from the Korg (or vice versa!), and a layer of the two for a RH sound.

That's just about close to impossible, right now.

We need standardization of the codes to select fills, Variations, Intros and Endings, Breaks and Break/Fills, transposition and a few other things at the very least. At the moment, there is zero compatibility between manufacturers on these common to ALL features.

Until we get them, combining two arrangers is a crippled duck.