Except that the Dutch Caribbean definitely has its own bilaterals - it isn't even included on the Dutch ones, both for the US and South America.
I was involved in a project quite a while back to create a hub connecting north-south traffic flows in one of those islands, to take advantage of the US Immigration and Customs pre-clearing (ie you can fly into domestic US airports, or into domestic gates on international airports).
In the end it came to nothing - but they are doing quite well in their point-to-point US traffic.