Binding off Visibility of another element - and inverting

I'd like to make Control A visibile if Control B is hidden, and vice versa. Right now I have this converter:

public class InvertVisibilityConverter : IValueConverter {

    public Object Convert(Object value, Type targetType, Object parameter, CultureInfo culture) {
        if (targetType == typeof(Visibility)) {
            Visibility vis = (Visibility)value;
            return vis == Visibility.Collapsed ? Visibility.Visible : Visibility.Collapsed;
        }
        throw new InvalidOperationException("Converter can only convert to value of type Visibility.");
    }

    public Object ConvertBack(Object value, Type targetType, Object parameter, CultureInfo culture) {
        throw new Exception("Invalid call - one way only");
    }
}

And this XAML:

<Button Visibility="{Binding ElementName=btn1, Path=Visibility, Converter={StaticResource InvertVisibilityConverter}}">Btn2</Button>

Which works. I'm just wondering if there's a more direct way in WPF / Silverlight to accomplish this? I don't mind having a converter, I just want to make sure there's no better way I'm not aware of.