Question is purely hypothetical. So the scenario of A + B present indeed needs a specific solution.
I only just start to get going with Hazel and am thinking about a 'total solution' for tackling the paperless issue.
It starts out as 'a couple of rules' to capture 'most' recurring paper, then you start to think further and think about gradually elaborating, so I'd need a 'catchall if not fitting any previous rule', and build additional rules from there.
For me, to keep it more or less manageable, I need some 'visual' logic from left to right stepping through rules, and sorting from e.g. stage 1 > stage 2 > stage nn.
So I was already missing subfolders in the preferences pane.
That also leads to wishing / trying to integrate as much into 1 rule instead of doing it in multiple steps.
Just my thoughts.
Erwin