How to use /ignore against irssi events?

Hi,

when users quit, there will be an info message like 'xxx has quit
[reason]' in both channel and private message window (in case you
have open queries) - now, is there any option to ignore only
quit messages in private windows?
The /ignore command did not do the trick so I tried to set up
a little script like this:

> sub hideQuit {
>    my ($server, $data) = @_;
>    my ($target, $text) = split(/ :/, $data, 2);
>
>    if ($server->{tag} eq "bitlbee") {
>            Irssi::signal_stop();
>    }
> }
>
> Irssi::signal_add("event quit", "hideQuit");

How do I combine "event quit" and "event_privmsg"? What I am trying
to do is avoiding lots of status changes (saves a lot of time when
using irssi on small displays like smart phones).

Many thanks,
Amadeus