<TelerikRadioGroup Data="@RadioData"
                   @bind-Value="@ChosenOption"
                   ValueField="Child.Id"
                   TextField="Child.Text">
</TelerikRadioGroup>

@code {
    public int ChosenOption { get; set; }

    public class Parent<TItem>
    {
        public TItem Content { get; set; }

        public Parent(TItem item)
        {
            Content = item;
        }
    }

    public class Child
    {
        public int Id { get; set; }
        public string Text { get; set; }

        public Child(int id, string text)
        {
            Id = id;
            Text = text;
        }
    }

    public List<Parent<Child>> RadioData { get; set; } = new List<Parent<Child>>();

    protected override void OnInitialized()
    {
        RadioData.Add(new Parent<Child>(new Child(0, "Item 1")));
        RadioData.Add(new Parent<Child>(new Child(1, "Some text")));
        RadioData.Add(new Parent<Child>(new Child(2, "Other text")));
        RadioData.Add(new Parent<Child>(new Child(3, "Third text")));
        base.OnInitialized();
    }
}