I havent see this option so far on Chile or USA, but today i was checking on Ecuador Site and this site came out.
You can ask for it on this routes so far
Santiago - Sao Paulo.
Santiago - Río de Janeiro.
Buenos Aires - Sao Paulo.
Bogotá - Sao Paulo.
Lima - Sao Paulo.
None are from Ecuador so i have no idea why they put them on that site first
