Irules Data-Group

Let me tackle the easy part - mapping the virtual name into a pool name;

 Choose pool base on virtual name,  checking for an error
if {[catch {pool [string map {"www." "pool-" "HTTPS" "HTTP"} [virtual]]}]} {
    log local0. "pool [string map {"www." "pool-" "HTTPS" "HTTP"} [virtual]] not configured"
}

Unfortunately I cannot quite understand what it is you want to do with the data-group. They are simple but I am somewhat confused by the explanation above.