Dynamic HTTP Forward Proxy based on header value

Hello,

 

I have a transparent virtual server for http requests.

 

i would like to dynamically forward some of the requests to an http proxy.

 

i dont know the proxy's address i should forward the http request to, it is appeard in a specified header if it needs to be done.

 

therfore i cannot create a pool with the known proxy servers and use an i rule with switch .

 

so my question is if there is an option (which i cant find in any irule documentation) to forward to an external http proxy based on the address appeared in the specific header.

 

would appriciate any help.

 

thanks