APM SSO to different portal based on URI

Hi.

I am struggling to find the best way to achieve the following.

I have a front end url of https://server.domain.com which succesfully grants access via APM to a backend server with SSO.

What I need to do is to send https://server.domain.com/path1 to a different backend server with an SSO portal

I've looked at iRules and portal rewrites, but can't find the right combination of how to get this to work.

Thanks in advance,

James.