Create a pool with port forwarding

Honestly, it sounds to me as though the best approach would be to create individual VIPs to listen to the three ports you actually want to pass traffic on, since it would be additional overhead to block/drop everything else manually.

This could certainly be done, though, so option B is definitely possible. The statement you'd want in your iRule would be something like:

when HTTP_REQUEST {
  switch [TCP::local_port] {
    2001 -
    2002 -
    2003 { pool jbossPool }
    default { discard }
  }
}

This would look for anything that comes in destined to port 2001, 2001 or 2003 and send them along to a pool, in this example named jbossPool, and discard everything else.

HTH,

Colin