[syslog-ng] Does syslog-ng support triggers?

Hello everyone, I was wondering if syslog-ng supports triggers (based on keywords OR time events). Ie: i want to be able to call an application if syslog-ng detects the same log message came from the same host x times in y minutes. We are suffering a lot of attacks against our webmail servers and would like to use this to try and trigger an alarm against brute force connections. Thanks in advance, -- Luís Miguel Ferreira da Silva Qualidade e Segurança CICA - FEUP GSM: +351 912671471