Grouped Bar + Stacked Bar Chart in the same chart

[shaila amorini]

I have to make a chart half Grouped Bar and half Stacked Bar.

For example i have:

 var data = google.visualization.arrayToDataTable([

         ['Month', 'Bolivia', 'Ecuador', 'Madagascar', 'Papua New Guinea', 'Rwanda', 'Average'],

         ['2004/05',  165,      938,         522,             998,           450,      614.6],

         ['2005/06',  135,      1120,        599,             1268,          288,      682],

         ['2006/07',  157,      1167,        587,             807,           397,      623],

         ['2007/08',  139,      1110,        615,             968,           215,      609.4],

        

      ]);

i need 2004/05 + 2005/06 displayed as Grouped Bar Chart AND 2006/07 + 2007/08 displayed as Stacked Bar Chart in the same Chart. Is it possible? I need it NOT as an Image Chart. I searched in Combo Chart but i didn't find any solution that worked...

Thanks and sorry,

S.A.