我的MVC模型应该如何与我的业务逻辑类一起使用？

So I have a MVC app and in another project I have a normal collection of classes which handle the Business and Data logic for the application. I also have some logic in the Model of the MVC project itself. This logic handles ViewModels and the like, things which could not have been done in the n-tier project as they relate to the MVC project itself and need to be in the same project. So I have a MVC app and in another project I ha