Most cassettes have the first 3 or so cogs as a single piece so you couldn’t swap the spacers between them. Maybe on some cassettes you could but I wouldn’t imagine it’s something available to buy.
None of the ones I have are blocked together, they are all independent. It seriously cannot be hard to 3d print a spacer set for Shimano that fits the Campy splined freehub.
Most cassettes have the first 3 or so cogs as a single piece so you couldn’t swap the spacers between them. Maybe on some cassettes you could but I wouldn’t imagine it’s something available to buy.