I'm currently working on a large-scale orchestra arrangement. One of the things I'm having trouble with is naming staves/groups. More specifically, there are times where I would want three staves for horns, and times I only want two (I already know how to hide the third staff in certain sections). The horns would be in a groups that is named such, but the staves that show the part division (see image), I have no idea how to change it mid-score. I only know you can make the first page different from the rest (because abbreviation), but that isn't what I'm looking for. This also happens in a few other instruments (flute switching to piccolo, bassoon to contrabassoon, etc.), but it's most prominent/common in the horns.

Along similar lines, I also have a keyboard player switching from one keyboard to another a few times. This is essentially the same issue, but I need to change a group name mid-score instead of a staff name.

If anyone knows how to do any of this, I thank you in advance.