It's fairly easy, I suppose. In Hispanophobe SoAm, it may be neccesary to reduce Amerindian cultural influence, as this is the main reason that some of the Hispanophobe states didn't mesh.
The choices I can think of for SoAmerican 'superstates' are:
1: Brazil. It's fine enough as is, except maybe give it the Guyanas.
2: A La Plata centered state not too dissimilar from the UPSA from Thande's LTTW. Argentina, Chile, Uruguay, Paraguay, possibly Bolivia and Peru.
3: Gran Colombia survives: Venezuela, Colombia, Ecuador, and possibly Peru.
4: Some sort of Amerindian state consisting of Paraguay, Bolivia, and highland Peru. Highland Brazil, northern Argentina, and Andean Ecuador and Colombia could also be included.
5: Uber Guyana: The three Guyanas plus Venezuela and a huge chunk of Brazil.
6: Patagonia/Araucania: Or something of the sort, inolving Argentina and Chile.
Obviously not all of these could exist simultaneously, but I'm sure a stable situation where at least three exist is possible.