iRule under f5 box not under virtual server

Our solution use many virtual servers and differnetiate between them using port number but we need to create iRule to redirect customer to his virtual server. mean when customer write https://1.1.1.1/zzz redirect to https://1.1.1.1:100/zzz and set virtual server zzz and if another customer write https://1.1.1.1/yyy redirect to https://1.1.1.1:101/yyy and set virtual server yyy. Note: we can't apply iRule under virtual server as we differntiate between virtual server using port number but customer not write port number at his [HTTP::host] so we can't apply iRule under virtual server. can any one advice us.