Kendo Grid默认分组（多个字段）和聚合格式

Question

以下是我到目前为止所做的代码片段。

                $("#grid1").kendoGrid({
                    dataSource: {
                        transport: {
                            read: { url: "@Url.Action("GetDetails")", data: { projectId: '@Session["ProjectId"]' }, type: "GET", dataType: "Json" }
                        },
                        pageSize: 20,

                        group: [{ field: "EmployeeName", aggregates: [{ field: "Effort", aggregate: "sum" }] }, { field: "Start", aggregates: [{ field: "Effort", aggregate: "sum" }] }]

                    },

                    toolbar: kendo.template($("#template").html()),
                    //   groupable: true,
                height:"750",
                    sortable: true,
                    filterable: true,
                    reorderable: true,
                    navigatable: true,
                    selectable: "multiple",
                    columnMenu: true,
                    resizable: true,
                    pageable: {
                        refresh: true,
                        pageSizes: true,
                        buttonCount: 8
                    },
                    dataBound: onDataBound,

                    columns: [
                    {
                        title: "#",
                        template: "#= ++record #",
                        width: 30
                    },

                {
                    field: "EmployeeName",


                    hidden: true,
                    groupHeaderTemplate: '#= ResourceTemplate(value)#'

                },
                {
                    field: "ProjectCode",
                    title: "ProjectCode",

                },
                {
                    field: "Geography",
                    title: "Geography",


                },
                    {
                        field: "Manager",
                        title: "Manager",


                    }, {
                        field: "Title",
                        title: "Task",

                    },
                 {
                     field: "Effort",
                     title: "Effort",

                     aggregates: ["sum"],

                     groupFooterTemplate: "Total Effort: #=sum# hours"
                 },
              {
                field: "Rate",
                title: "Rate",
                groupable: true
              },
               {
                field: "Frequency",
                title: "Frequency",
                groupable: true
               },
                 {
                    field: "Start",
                    hidden: true,
                     title: "Date",
                     format: "{0:dd/MM/yyyy}",

                     filterable: {
                         ui: "datepicker"
                     },
                     type: "date"
                 }


                    ],
                    dataBinding: function () {
                        record = (this.dataSource.page() - 1) * this.dataSource.pageSize();
                    },
                    change: function (arg) {
                        var selected = $.map(this.select(), function (item) {
                            return $(item).find('td').first().text();
                        });

                    },
                });

默认情况下，网格按EmployeeName和Date分组。我只想要员工的总工作量（44小时），但是按日期分组会导致日期明智的总工作量（6小时28小时）也不需要。我怎么能避免这种情况。