Ford, I believe you can do it as such:

alias parsemode {
  noop $regex($1,/(?!\54)([+-][ $+ $chanmodes $+ ])/)
  return $gettok($regsubex($1,/(\S+)/g,$+($regml(1),\1)),2-,32)
}

You merely need to specify one +b or -b to have all the strings prefixed with a channel mode.> //echo -a $parsemode(+b this that theother)will return > +bthis +bthat +btheother