Different "Voices", Different Instruments

It would be the coolest idea if different parts or different lines of a staff were assigned different instruments. I know that this was already discussed for the choir side of this, and that Musescore already comes with a general orchestral percussions drumkit but sadly its not compatible with the new sounds, and if I do apply the new sounds, it automatically sets the drumset to the instrument sound. I've also tried assigning different instrument changes to different voices and that's also really...something..(didn't work)

It sounds like such a simple feature thats so commonly used in sheet music so I hope it has a chance of coming out in 4.5