[CentOS] Remove all packages from specific repository

Hi CentOS Mailinglist,

we are using amavisd-new (with all dependencies) from Fedora/Redhat EPEL repo. Some packages from EPEL repo are very old. (amavisd-new, clamav, spamassassin)

What's the best way to remove all amavisd-new packages (and it's dependencies) from EPEL repo and reinstall it from rpmforge repo?

Thank you.

Best regards,

Morten