I hope I understand this right -- for each pie series you want to have different set of colors. What you need to do is to iterate through each item in each series.
ChartSeries series1 =
series1.Type = ChartSeriesType.Pie;
Color colors = (
i = 0; i < series1.Items.Count; i++)
series1.Items[i].Appearance.FillStyle.MainColor = colors[i];
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