VIP with multiple pools and TCP ports

It seems inefficient to me, but if you must use an iRule, I would probably use a switch statement. Since it's a simple mapping, I'm not sure I would feel the need for a data group.

when CLIENT_ACCEPTED {
    switch [TCP::local_port] {
        "901" { pool pl_901 }
        "902" { pool pl_902 } 
        "903" { pool pl_903 } 
        "904" { pool pl_904 } 
        "905" { pool pl_905 }
        }
}

I would also wonder if there is a need for separate pools. If the VS uses the ANY port and the pool members are all the same between ports and use the same port as the VS, just use the ANY port on the pool and let it carry over.