主题：如何加条件分组统计

Dim bd4 As New sqlGroupTableBuilder("统计表4","pzk")
bd4.C
Dim dt4  As fxDataSource
bd4.Groups.AddDef("付款_所属项目","项目分类")
bd4.Groups.AddDef("付款_收款方","材料供应商")
bd4.Totals.AddDef("付款_金额","已付金额")

我要在bd4.Totals.AddDef("付款_金额","已付金额")中如何加条件，只汇总pzk表中列名为“报销”的内容不参与汇总。