Shipping configuration question

[JaxMusicSupply]

Hi folks.   I have a question about shipping configuration.   I use a flat rate shipping model, basically free for all US (built into the price of the products) and a weigh range based model for countries outside of the US. Basically the foreign rates come down to Canada, South America, and the rest of the world.  However, the geographic range of the shipping that is included basically has ranges only for very broad geographic areas, not countries.  I can choose North America, but not Canada (or Mexico, or USA).  I can choose South America, but not have a different rate for Brazil versus Argentina.  Is this correct?  Do I need to purchase a module that does this?  I find it surprising that North America would be lumped in all together.  Thanks in advance for advice and assistance.