Condensing Change not available

In a long multimovement work I have 8 horns that I want to be able to switch between a2, a4 and a8 staves mainly. I started out with a2 and now want to create a8.

However in the Condensing Change window I cannot select all the horns in the Manual change window.

Also as you can see from my screenshot: Is there a way to get horns 7 & 8 to group? They are like that because they double Tuben. Grouping them in the Setup mode doesn’t work.

You can’t combine different condensing groups with manual condensing but you can split up a group onto different staves.

So, you need to create one group with all 8 horns in Layout Options, and then split it up in different ways with condensing changes.

Dorico can’t handle instrument changes in condensing at present. You might be better making your tuben separate players in Dorico and letting the unused staves be hidden, and then adding your own instrument change text where you need it. You might have to add a system break where the players change instruments, but that probably doesn’t happen very often.