Routing incoming emails to different servers based on email address

I use Google Apps for my company email. We would like certain emails to be handled by an application. These emails are part of the service we provide. So, what we want is:

emails to [email protected] get handled by a special mail server emails to [email protected] get handled by Google Apps

I want both emails to have the same domain.

I could set up a route within Google Apps, but [email protected] gets a lot of email very frequently. Google Apps has throttling, I need to make sure this email is NOT throttled.

How can I route incoming emails to different mailservers?