The Rules have sub-categories.
Defining an evolutionary path to integrate improved or expanded Rules is worth exploring.
For instance a built-in variation of the 2nd suggested Rule exists as:
- Families → General filters → Descendant families of <family>
But it does not allow specifying a Person or (Person/Family) filter. Nor does it optionally allow the Generations to be limited. Nor optionally limit to Biological descendants.
So an add-on could be developed based on the built-in. And, after it is tested and optimized, the add-on might replace the built-in.