Double header in ALV

Hi all.

I am trying to do an ALV report with an agroupation of fields. This means that they want to display the ALV header in this format:

                                             Group 1                                             Group 2

Key_field_1     Key_field_2     Field_1A     Field_1B     Field_1C     Field_2A     Field_2B     Field_2C

Do you know if this double line in header is possible? If so, how can I do it?

Thank you to all in advance.