In Visual Studio click on the DeveDefind reference under the References section and you'll see a property of the reference called Aliases and it'll be "global" by default. Change that to something like "DeveDefind". Now when you reference a class inside DeveDefind rather than referring to it like;
MyNamespace.MyClass
use;
DeveDefind::MyNamespace.MyClass
That will tell the code explicitly which DLL to use for MyClass.