Transfers in South America-help?

OK-we have flown AA and Lan from the US to Chile/Argentina. Our bags can be checked through because they are partners. Therefore, we can start from Philly, go through Miami, arrive in Santiago, go through transit and our bags arrive in Mendoza. (even though there are two tickets for this trip.) Now...the question.....If we fly United or Delta from the US to Santiago and then change to Lan or Aerolinas Argentinas in Santiago and head to Mendoza, will we have to reclaim our bags and then go through customs? Has anyone changed carriers and can share this experience...THANKS!

Once Aero Argentinas is approved as Skyteam member (sometime this year), you will be able to do that with DL gateway flight. I'd email DL or call them to ask about check-thru---they may also have a date for AR joining the alliance.

Thanks K! It would be a nice option to fly Delta and Aerolinas to Argentina. Hope it happens soon!