Say I’ve got a great jazz template. Groove Agent [Simon Phillips Jazz Drums]. And I’m creating several flows within the template. I want Full Swing Brush to be the preset for Flow 1, and Jazz Waltz Brush for Flow 2.
When I play or work on those individual flows, is there a means by which I can get those flow-specific presets to load into Groove Agent automagically? Or must they be loaded in manually?
No, there’s no way to do this automagically. In general you will find that the tempo sync between Dorico and Groove Agent SE fails after the first flow anyway, unless you set the gap between flows in Playback Options to 0 seconds.
Wait, what? If I understand you correctly, Groove Agent will only sync properly for Flow #1? And after that it’s catch-as-catch-can? How is this remotely conscionable? I am dialing Fiona Bruce and Philip Mould right now. And Amnesty International, too.
[I get it. Each flow must be dealt with individually including exporting audio. I understand why. But expect a harsh call from Fiona in the morning, and a resounding dis-endorsement from Philip Mould.]
I have some nice pictures stuck to my fridge door with magnets that Mr Mould is welcome to assess.
It would take 1½ hours of artistic forensics, at least 45 minutes of heavy on-screen monologue, and a battery of art technologists to ascertain the provenance, authorship, and ultimately worth-at-auction of your fridge pictures.
I await a proper assessment.
Losing the thread of this thread 
Well yeah hadn’t thought of that, of course a VST is frozen for the piece. Well in that case I’d export the MIDI and import into Nuendo, and break it out manually. Seems to be the only way to do it?