But I've got a notion that reads like a fix-up, even if fix-ups are a lot less common than they were. (Something about declining markets for short stories, so it's less profitable to break it up first.) Still, it's not impossible, even today. And who knows? The book may demand to be written that way.
In this case, because it involves a fair sized set of characters set loose in a common setting, and each one of them having episodes of their own. A strongly unifying setting, especially since they all have an over-arching purpose, despite their different motives, that will keep them together -- and their stories colliding together, too.
Which makes it interesting considering the outline. Do you split up the stories into separate outlines? It helps keep the stories intact, like beads strung on the necklace. To the point where it would force them separate, even if I'm wrong about whether this story can be broken up into sub-stories. Requiring later revision to reintegrate them into a novel. . . .
Come to think of it, that's not exactly uncommon while fixing up the fix-up.
Now, if only I could decide whether it's really the elemental world setting idea I've tried other stories out on, and none clicked.