Hello Abhishek,

As far as I understand your goals  when a row is selected according to some conditions a column have to be hidden or shown. It is easy to be done on the event RowSelectionChanged on the client.  Here is a template of the javascript event:

function WebDataGrid1_Selection_RowSelectionChanged(sender, eventArgs)

        {

            if (sender._behaviors._selection.get_selectedRows().getItem(0)._index % 2 == 0)

            {

                sender._columns.get_column(2).set_hidden(true);

            }

            else

            {

                sender._columns.get_column(2).set_hidden(false);

            }

        }

Hello Abhishek,

What you are describing is not a supported scenario. Cell merging is not a supported issue in WDG or WHDG. The best option for you is to hide column as already described. If you want to see this option in our controls please feel free to request it on the following link - http://devcenter.infragistics.com/Protected/RequestFeature.aspx