Group Cells value in GridView in ASP.Net

public void GroupColumnValue(GridView gvLoadingData, int ColumnIndex)
{
int ItemIndex = 0;

foreach (GridViewRow gvr in gvLoadingData.Rows)
{
gvr.Cells[ColumnIndex].VerticalAlign = VerticalAlign.Top;
gvr.Cells[ColumnIndex].Font.Bold = true;


if (gvr.RowIndex > 0)
{
HyperLink hl1 = (HyperLink)gvr.Cells[ColumnIndex].FindControl("hlUrlArea");
HyperLink hl2 = (HyperLink)gvLoadingData.Rows[gvr.RowIndex - 1].Cells[ColumnIndex].FindControl("hlUrlArea");

if (hl1 .Text== hl2.Text)
{
gvr.Cells[ColumnIndex].Visible = false;
gvLoadingData.Rows[ItemIndex].Cells[ColumnIndex].RowSpan = gvLoadingData.Rows[ItemIndex].Cells[ColumnIndex].RowSpan + 1;

}
else if (gvLoadingData.Rows[gvr.RowIndex - 1].Cells[ColumnIndex].Visible == true)
{

ItemIndex = gvr.RowIndex;
}
else
{
gvLoadingData.Rows[ItemIndex].Cells[ColumnIndex].RowSpan =
gvLoadingData.Rows[ItemIndex].Cells[ColumnIndex].RowSpan + 1;
ItemIndex = gvr.RowIndex;
}
}

}
gvLoadingData.Rows[ItemIndex].Cells[ColumnIndex].RowSpan = gvLoadingData.Rows[ItemIndex].Cells[ColumnIndex].RowSpan + 1;
}