Spam Filtering the nonexisting users

[SpireJ]

I have a problem with nonexisting users, there is a lot of spam. I don't wanna block the receiving mail for nonexisting users but a got a lot of spam on them. Is there a way to reduce this, I've read something about BAD_RCPT_THROTTLE and it will drop the connection if the sender specified more than 5 nonexisting recipients. How to use this, can someone elaborate
thx

 

[SpireJ]

So noone knows how to stop this nonexisting users sending me Viagra offers ???