HTTP Response - IRULE based on node/pool

I have a requirement to perform a certain action based upon "NODE" and/or "POOL" on the HTTP response.

 

Example:

 

GET http://www.abc.xyz/123 will send to NODEA - during the process will be rewritten to /xxx when sending to NODEA (this works) GET http://www.abc.xyz/456 will send to NODEB - during the process will be rewritten to /xxx when sending to NODEB (this works)

 

On the return traffic based on the NODE we will want to rewrite back to the original URI (I have this working for a single URL by a general HTTP::Header value. The trick is to make it such that the /xxx coming back from the specific NODE gets rewritten to the correct URI that originated. Hope this makes sense.

 

In reading I suppose I could look at the NODE IP and do it that way, but wondering if there is another way at looking at the response source NODE? I also see DNS is an option, but not looking at taking that direction. Thanks.