How to group the value of an IEnumerable property

Let's say I have

class Class1 A {
    int Id;
    IEnumerable<Class2> B;
}

class Class2 B {
    string Title;
}

      

        
        
        
      

    

So, if I have (in json format)

{Id: 0, B: [{"Title": "a"}, {"Title": "b"}, {"Title": "c"} ]}

      

        
        
        
      

    

I want to group Title

, so the result will be

 { {"Id": 0, "Title": "a"}, {"Id": 0, "Title": "b"}, {"Id": 0, "Title": "c"} };

      

        
        
        
      

    

Prefer LINQ solution. Tried to do:

var result = A.GroupBy(x => x.B)

      

        
        
        
      

    

(I expected this to not work) and

var result = A.SelectMany(x => x.B).GroupBy(x => x)

      

        
        
        
      

    

but then I only have titles. How can i do this?