Comment 1 for bug 874449

It looks like Search.pm might be the place to start for this. Particularly:

    my $site;
    my $org = $ctx->{search_ou};
    if (defined($org) and $org ne '' and ($org ne $ctx->{aou_tree}->()->id) and not $query =~ /site\(\S+\)/) {
        $site = $ctx->{get_aou}->($org)->shortname;
        $query .= " site($site)";
    }

For what it's worth, I actually can't make this work either. Seems this may be completely busted. Shame, because its a nice shortcut!