Hi,

I do not speak spanish but I ran your text through google translate and it looks like you want to change the order of the group by column display based upon the # of child rows for that group by row.  Correct?

<http://help.infragistics.com/NetAdvantage/WinForms/2010.3/CLR2.0/?page=Infragistics2.Win.UltraWinGrid.v10.3~Infragistics.Win.UltraWinGrid.UltraGridColumn~GroupByComparer.html>. 

This help link is the GroupByComparer property of an UltraGridColumn and it shows how to do what I think you want to do (if the translation was correct...)

For example using the Northwind Orders table as the source for the grid you could do the following:

        private void ultraGrid1_InitializeLayout(object sender, InitializeLayoutEventArgs e)
        {
            UltraGridColumn countryCol = this.ultraGrid1.DisplayLayout.Bands[0].Columns["ShipCountry"];
            if (countryCol != null)
                countryCol.GroupByComparer = new MyGroupBySortComparer();
        }

    class MyGroupBySortComparer : IComparer
    {
        public int Compare(object objx, object objy)
        {
            UltraGridGroupByRow x = (UltraGridGroupByRow)objx;
            UltraGridGroupByRow y = (UltraGridGroupByRow)objy;

            return x.Rows.Count.CompareTo(y.Rows.Count);
        }
    }

You will probably have to run this text through a google translate as well to read what I've written.  Let me know if this is the behavior you were trying to achieve.