The owner code would be something like this. I also put it all in one on text event to make it shorter.

on :text::*: {
if ($nick == %owner) && ($1 == !join) {
/join $2 | msg # $me has join $2
}
elseif ($nick == %owner) && ($1 == !leave) {
/part $2 | msg # $me has left $2
}
}