spanning in datagrid

datagrid? .NET DataGrid?
Normally, No..

You have overrides one events of DataGrid then you can customize it as you like.
I'd recommedated you to read CuttingEdges Columns from MSDN mag as much as you can.
You may got some good ideas..

Here is some links ~
Extend the ASP.NET DataGrid with Client-side Behaviors
http://msdn.microsoft.com/msdnmag/issues/04/01/CuttingEdge/

Moving DataGrid Rows Up and Down
http://msdn.microsoft.com/msdnmag/issues/05/03/CuttingEdge/

Build a Variety of Custom Controls Based on the DataGrid Control
http://msdn.microsoft.com/msdnmag/issues/01/10/cutting/default.aspx