Hi,

You can achieve this by implementing a custom merged cell evalutor for the columns you want to alter the merged behavior. 

To get you started you can create a class that implements the IMergedCellEvaluator interface and assigning it to a column:

class CustomCellMerger : IMergedCellEvaluator
    {
        public bool ShouldCellsBeMerged(UltraGridRow row1, UltraGridRow row2, UltraGridColumn column)
        {
            if (!row1.Cells["Symbol"].IsMergedWith(row2.Cells["Symbol"]))
            {
                return false;
            }

            return true;
        }
    }

Back at the grid set the column to use this evaluator:

private void ultraGrid1_InitializeLayout(object sender, Infragistics.Win.UltraWinGrid.InitializeLayoutEventArgs e)
{
     e.Layout.Bands[0].Columns["Expiration"].MergedCellEvaluator = new CustomCellMerger();
}

Continue this out for the other columns you want to modify the merged cell behavior for and you can implement the merging behavior you were after.