I use Zimbra 8.0.2_GA_556

I use blacklist_from method in for custom blacklist. I edit this file /opt/zimbra/conf/spamassassin/local.cf and write rules as below

blacklist_from *@*toplu*
blacklist_from *@mrom2.com

It works perfectly. Now i try to set blacklist_to method. I don't know that there is a method like this. For example

blacklist_to groupname@yahoogroups.com

I want to block some groups mail. I have to use "to" section in email, because i don't want to block users.

How can i do it?