Pool redirect based on source IP and port

Try using the TCP::local_port data item, whose value should be either 80, 443, or 808 depending on which virtual server is being accessed.

when CLIENT_ACCEPTED {
switch [IP::addr [IP::client_addr] mask 255.255.255.0] {
    "1.1.1.0" -
    "2.2.2.0" {
        pool www.site.com-[TCP::local_port]
    }
  }
}