"views" - how to display a list of parent nodes? which arg() should I use?

Hi,

I would like to display a list of nodes that is under "airfare" when I'm at "north america". It means to display a list of nodes of it's parent.

Home » Airfare » North America

this is what I have to display "airfare" list when I'm at "airfare".

$view = views_get_view('top_10_list');
print $view->execute_display('default', array(arg(2)));

I tried the following code to display "airfare" list under "airfare/north america" but with no success.

$view = views_get_view('top_10_list');
print $view->execute_display('default', array(arg(2),arg(3)));

could someone help? Thanks