amCharts 4饼图-如何将较小的切片合并为一个？ v4中缺少groupPercent

Question

我正在测试amCharts4。在amcharts 3中，有一个groupPercent属性可以将较小的切片组合成一个饼图。

"groupPercent": 1.1,

https://www.amcharts.com/dataviz-tip-18-combine-smaller-pie-chart-slices/

amcharts 4的等效物是什么？

https://www.amcharts.com/docs/v4/reference/pieseries/

var series = chart.series.push(new am4charts.PieSeries());