redirect when all nodes in pool down

Hi,

 

I am a very new person to irules but the item above interests me a lot. I am trying to implement a redirect above . What i am trying to do is, if 2 members in a pool fail(i.e. 3 members in the pool), then we should redirect all traffic to a new server which would be something like Http://172.24.38.17. The problem is that we need to pull the port for the redirect from the header of the messages. For instance in the messages will be "HOST: hello.hello.net:8003" it can also contain "HOST: hello.hello.net:8004". For these messages we should pull the port from this(i.e. 8003 or 8004) and redirect to Http://172.24.38.17:8003 or http://172.24.38.17:8004 depending on the incmoming message.

 

 

Any help would be great or if you need any firther clarification/.