[otrs] Block or reject emails?

Hi, Is there a way I can block or reject emails in OTRS and also not sending out automatic replies to certain specified addresses? We have some problems with some newsletter-junkmails and some endless loops that are filling up our RAW inbox ... We're using an external POP3 server and I can't set up anything on that side... I'm running an older v. 2.4.7. Thanks! Andy