Natively, no, it cannot. There are numerous ways to add in alerting capabilities with user space tools such as the IDS snort (http://www.snort.org).
Q:
Can firewall rules be used to route traffic based on the recipient?
A:
The short answer is no. The (very) long answer is yes, but you would need to use something like iproute2 (ftp://ftp.inr.ac.ru/ip-routing/) or an application layer proxy. It is also possible to use firewall rules to route SMTP traffic destined to one machine, to another machine using a redirect rule that can be used to do inline filtering (spam, scanning, and so on) on that traffic. It would be up to this third-party system to then send the processed SMTP traffic to the original destination.
