Hi benjam, I can see two options here:
A. If you have some Business Classes, you could enforce the use of subclasses by demanding them from methods:
public void DoSometihng(MyCustomerEntity customerToUse)
B. Use the "General preset" (not "Two Classes"). This way you could write your business logic at partial classes and the programmers have only one class to instantiate.
Why did you choose "two classes" scenario over "one class"?