Redirect TCP port from HTTP request to another port in a pool

Hello,

I've got this rule for a virtual server on my F5 BIG-IP:

 
 when HTTP_REQUEST { 
     switch -glob [string tolower [HTTP::host]] { 
            "my.local.domain:*" { pool locdompool } 
            default { reject } 
     } 
 } 
 

locdompool is a pool with one server, that listens on all ports.

So when you type http://my.local.domain:1234 you will be redirected to the server at locdompool port 1234.

Now I want one port to be redirected to another one in that pool. I.e. port 1234 should go to port 5678 in locdompool. How can I do this?

Thanks and best regards

Matthias