Parts: Also select the voice of the instrument to create a part

It would be very helpful if it was possible to not only select the instrument but also the voice to create a part of. In a full score you often notate several voices in one staff. But when you give your piece of music to the musicians it is better if every musician has a sheet with only his voice.
For example: In your full score you notate the 1st and 2nd French Horn in one staff but you want to give your 1st horn player a sheet with only the voice he has to play and the 2nd horn player a sheet with only his voice. So the players are not disturbed by unneccessary voices that make the reading more difficult.

I know that you could archieve this by making the voice you don't need in a part invisible. But this isn't dynamic. If you change something in the full score you have to go into all your parts to make the unneeded voices invisible again.

The next step would be to make it possible to notate a "uni sono" in the score and the following voice shows up in all parts of all voices. But that's the advanced stuff.