Nhibernate：在相同的2个实体之间映射两个不同的属性

I have a Class A:

我有一个A类：

public class ClassA
{
      public int ID {get; private set;}
      public string Code {get; private set;}
      public ClassB B {get; private set;}
      public IList<ClassB> ListB {get; private set;}

}
public class Clas