how can I let Json Serializer ignore the enumeration of a class and serialize it as object and list it’s properties only.

Here is an example of my problem:

public class ObjectList<T> : IEnumerable<T> where T : class
{
    public ObjectList()
    {
        this.Items = new List<T>();
    }
    public string Group { get; set; }
    public int Count { get => this.Items.Count; set { } }
    public List<T> Items { get; set; }

    public IEnumerator<T> GetEnumerator() { return this.Items.GetEnumerator(); }
    IEnumerator IEnumerable.GetEnumerator() { return this.Items.GetEnumerator(); }
}
public class ItemList : ObjectList<ListItem>
{
}

Assuming following content

var list = new ItemList() 
{
        Group = "Group",
        Items = new List<ListItem>()
        {
        new ListItem() { Name = "Foo"},
        new ListItem() { Name = "Bar"},
    }
};

Now when I serialize the content using following code.

var txt = System.Text.Json.JsonSerializer.Serialize(list, new JsonSerializerOptions()
{
    WriteIndented = true,
});
Console.WriteLine(txt);

I get the following output

[{"Name":"Foo"},{"Name":"Bar"}]

The properties of the list object (Group, Count, Items) are not listed. The result I expect would be as following:

{"Group":"Group","Count":2,"Items":[{"Name":"Foo"},{"Name":"Bar"}]}

Removing the enumeration from the main class ist not an option. So I need to tell the the serializer to handle the class ItemList as an object rather than enumeration.

Can you help me on that point?

Thank you in advance.