So this afternoon I disgruntledly (?!) went back to my Symphonians MS to start whipping it into shape. I had to shut off the computer that had internet access because I kept messing around on the internet instead of writing. Cripes.
And I'm looking at the first chapter, thinking, "You know, those two stories -- that is, the Kay story and the Symphonians bit -- actually went together pretty well right there." And so I took a bit of the Symph story from the other document I'd saved, and I dropped it into the first chapter. It nestled in all nice and tidy. I said, "Hm!"
So I went looking around in the book for another place where I could put a chunk of story, and what do you know, Wyatt and Kay were playing the same part in band (they play tuba and bass clarinet, respectively), and hey, in this Symph bit, Roderick and Violet were playing a song together on tuba and regular clarinet, so I dropped that chunk in right about there. And it looked nice there, too.
So NOW I have figured out how to fix the problem!
The Symph bits are big enough to give the reader a good idea of what's going on in their narrative, and they're right in Kay's text so she can comment on them. But their narrative is being kept to a bare minimum at this time so Kay can take center stage. But hey, I'm fine with that.
So I guess that sometimes you have to bring the world to an end to make something work. Though in the end it's actually a beginning.