detecting bridge head carbons atoms in larger cycles

[RobertArbon]

Hi folks,

I'm wondering if there is an easy way of detecting (and filtering) graphs with bridgehead atoms for rings larger than 4?

Specifically I would like to remove a graph if there is: a) 3 or more bridgehead atoms and b) each of those atoms is is involved in 3 (or more) rings. e.g.: CC12CC3(C)CC(CC(C2)C3)C1 :

In code for -B9 flag you detect whether an atom is involved in 2 or more rings of size 3 or 4. But this looks pretty specific to rings of 3 or 4. I wonder if there's a more general approach you would recommend?

Thanks!