datagridview header appearance

Question

hello all

in datagridview  dgv1 I have two column  header ,

column header "Amount" and column header "Date"

I want above these two column there is one header "Realization"


so it look like :

______________________________
|                                                          |
|                    Realization                     |
|_____________________________|
|                              |                           |
| Amount                 |  Date                 |
|_______________|_____________|

How to do that ?
hope any help

tq  denny