Using NDBPro Wrapper, (by Walaber) is there a way to prevent bodies joined from colliding into one another? For that matter, is there a way to prevent any two bodies from colliding into one another?

I found the answer. NDB_NewtonMaterialCreateGroupID can be used to create groups of objets, and NDB_NewtonMaterialSetDefaultCollidable can be used to set how groups of objects interact with one another.