SPAM - Same subject, different IP, from address

Hi Folks,

We just started getting some annoying SPAM on one account. We're receiving it hourly. Always with a different IP and different from address, but with the same subject line...

Nude Britney Spears , Shakria and Fergie on a new celebrity site


Any easy way to block this (preferably server wide)?

Something like...
apf -d 'some subject line'
???