Display property data list in complex object grouped by one of its fields

[Raul]

Hi,
I can`t achieve display the data from an Complex Object with a property List of subObjects, in the way I would like to Display. This Way is Grouping  the Field ‘Question’ by  ‘QuestionGroup’

Complex Object:
    public class QuestionnaireReportData
    {
        public string Name { get; set; }
        public string Description { get; set; }
        public string DeviceID { get; set; }
        public string SerialNumber { get; set; }
        public string Location { get; set; }
        public string City { get; set; }
        public DateTime Date { get; set; }
        public string Client { get; set; }
        public string Modelo { get; set; }
        public string Manufacturer { get; set; }
        public IEnumerable<QuestionResponseReportData> QuestionResponses { get; set;      }
    }

    public class QuestionResponseReportData
    {
        public string Question { get; set; }
        public string Answer { get; set; }
        public AnswerDataType AnswerDataType { get; set; }
        public string QuestionGroup { get; set; }
    }
I achieve to binding the sourceData of Table, List,etc to the List Property IEnumerable<QuestionResponseReportData>) and show Correct Data, But I don’t achieve to Grouping correctly by the Field QuestionGroup as I want.

This is what I would like to display (Good display attached image)

This is what I display actually (bad display attached image)

What I’m doing wrong? Thanks in advance!
Best Regards,

[Raul]

More info about the Issue and Working Environment.

Telerik Version: 11.2.17.913

Visual Studio: 2017 Community Version 15.4.1

Proyect Framework 4.6.1 / output Class Library