Exclude directories based on a dot file presence ?

Hi,

I'm wondering if something like this exists :

I'd like some directories to always be excluded from backups but
instead of having to everytime list them and potentially making
mistakes, I'd like every directory that has a ".rdiff-backup-ignore"
file (for instance) to never be included in backups.
Does something like that exists ? I couldn't see anything from the
doc, but maybe I missed it.

Cheers,

    Sylvain Munaut