This is what I'd do if I were you:

on $1000:text:/^!p(rivate|ublic)$/iS:#:{
  if $regml(1) = rivate { tokenize 124 $x | $y $!+(+, $* ) }
  else { tokenize 124 $x | $y $!+(-, $* ) }
}
alias -l y return scon -r mode $!decode( $encode(#,m) ,m)
alias -l x return $regsubex(m p i N C k 010100100PRIVATE01001010,/(m|p|i|N|C|k.*)/g,$+(|,\1))

One thing I'm confused about is that why do you check for ops and halfops when you indicate 1000 level for the on text event? Isn't that pointless?

P.S. I didn't implement a trigger control, but it's recommended so the client running the code doesn't get mode spam of flood in case that happens.