Sargento: Silverpie is right, the LatinPass airlines cover northern South America (Colombia, Ecuador, Venezuela, and Peru) but for travel around Brasil, Chile, Uruguay, and Argentina, the LatinPass airlines won't help much (unless you fly via Lima each time).

LatinPass allows you to combine miles for trips from different Latin American airlines, but for your trip plans, you may have to fly different airlines and earn orphan miles in different programs.

One thing to look for is flights between the capital cities on different international airlines, i.e. Lufthansa or British Airways for Buenos Aires-Santiago, Air Canada for Buenos Aires-Sao Paolo, and United or Iberia for buenos Aires-Montevideo..... right there, I put you on all Star Alliance carriers. :P Add in Varig for flights within Brasil, and you have it made.