One feature suggestion that has been made here is based on one of Finale’s more useful functions: staff sets. It would be very handy to be able to make a number of staff sets with different configurations in order to be able to do exactly what the OP was asking, among other things. I guess we can approach this by making layouts containing different staff configurations.
For what it’s worth, when I do coding in PyCharm or IntelliJ, I can create multiple carets by pressing Alt or Alt-Shift and left-clicking, and they all respond accordingly with keyboard commands. They can be moved by word using Ctrl+Left/Right, or moved to the beginning/end of a line with Home/End, even when they aren’t at the same vertical position. I hope similar functionality will be possible in Dorico someday!
Yes, I mentioned using layouts to simulate that functionality. In the long run, using Finale’s staff sets is only marginally quicker, as keyboard shortcuts are assigned to them.
If your score involves writing identical musical lines to constantly changing groups of non-adjacent instruments, creating a new layout each time (even if quickly accessible through shortcuts) seems more like a workaround (especially if the layout is not used anywhere else) compared with a caret you could extend anywhere you want.
This could be done in the following manner with mouse (but we could also think of a keyboard only solution), as proposed by @JesterMusician :