Count messages per host

Hi there,

I'm not capable of making this work.
I receive a lot of msg from several servers.
The kind of messages are the same through servers. What i want to do is count this kind of msg of each host (isolated by host) and if i receive 200 then send me an email.

Well i tried this with throttle but the key i use is the %{host} field. So it counts msg from all servers. What i want is count isolated each server.

server 1 -> counter 1
server 2 -> counter 2

So when server 1 receives 200 it sends me an email.