实体框架中基于多键（条件）的一对多关系

So I have

所以我有

class User
{
   ...
   public virtual ICollection<Book> AlreadyRead {get; set;} 
}

class Book
{
   ...
   public virtual User Owner {get; set;}
   public bool AlreadyRead {get; set;}
}
class User
{
   ...
   publ