Table - Grouping column cells

[Bader]

Hi,

I'm using the following code in order to group two columns by values.
I have a question regarding this issue: How can merge the grouped cells (Please view the attached image)?

c# code:

static string oldValueStatic = string.Empty;
        static string oldValueStatic2 = string.Empty;

        private void Nightly_ItemDataBinding(object sender, EventArgs e)
        {
            oldValueStatic = string.Empty;
            oldValueStatic2 = string.Empty;
        }

        public static string CutDuplicates(string data)
        {

            if (0 == string.Compare(oldValueStatic, data, true))
            {
                data = string.Empty;
            }
            else
            {
                oldValueStatic = data;
            }
            return data;
        }

        public static string CutDuplicates2(string data)
        {

            if (0 == string.Compare(oldValueStatic, data, true))
            {
                data = string.Empty;
            }
            else
            {
                oldValueStatic = data;
            }
            return data;
        }

I'm calling the functions as below:
= CutDuplicates(Fields.Env)

It is very appreciated to explain by supplying a step-by-step instructions how to solve the above issue.

Regards,
Bader