Best way to blacklist repository (maven.glassfish.org in site build)

Hello,

I have more and more projects (OSS and prop) where a lot of time is
wasted (especially in site builds) and also the number of error
messages or warnings to review increase with the vanished glassfish
repository.

The fact this happens is a major annoyance, but I do more
wonder on how to cope with it.

Is there an easy settings.xml based way to blacklist those repos, as I
cannot modify the already released external POMs which point to it.

(And please in the future do not add repos to your open source POMs!)

Gruss
Bernd