Now when Dorico support different midi channels for different voices in playback, is it also possible to assign different midi channels for each staff in a grand staff?
I’ve searched for an answer and I can’t find any information about it
btw Congratulations to the team for a great new version of Dorico! 
Forget my stupid question, I figured it out. 
Sorry I didn’t figure it out.
So I am able to set treble staff to send on ch1 and bass staff on ch2, and I can set my plugin to receive to the corresponding
channels.
However I need to have the treble staff to send transposed notes 12 st up and the bass staff to sen transposed -12 st, how do I accomplish that? Is it possible?
I can only set 1 transposition in the expression map.
I know I can load 2 plugins of the same and send treble staff to the first plugin and bass staff to the second, is that the best way to do it?
Sorry for messing things up.
Since I am developing this plugin I’m referring to (Accordion Converter Sample Library) I could of course script this transpositions directly in the plugin, but I wonder which way to go would be the best?
You’ll need to use two instruments held by the same player that you then bracket together with a brace in Engrave mode, so that each instrument can have its own expression map assigned.
Ok,thank you Daniel