for my $list (@lists) {
    printGroups($list->{groups}, %group);
    print $list->{line};
    print "\n";
}

##</code><code>##

sub uniq {
    my %seen;
    grep !$seen{$_}++, @_;
}

for my $list (@lists) {
    my @filtered = uniq(@lists);
    printGroups($filtered->{groups}, %group);
    print $list->{line};
    print "\n";
}