Grabbing Values for Filtering Kendo Grid

For the filter process, a multiselect works simply because it has it installed in the kendo grid ( filterable: { multi: true } ) and it grabs the values and puts them in checkboxes, but for a lookup filter where you say for instance ( starts with... and then theres another input where you Select a Value ), how do I grab the values from that column so the user can choose between what values in that Select input box? I have:

    <div id="grid"></div>

    $(document).ready(function () {
    datasource = new kendo.data.DataSource({
         type: "json",
         data: @Html.Raw(JsonConvert.SerializeObject(Model.Programs)),
         batch: true,
         schema: {
              model: {
                  fields: {
                       main: { type: "string" },
                       sub: { type: "string" }
                  }
              }
         }
    });

    $("#grid").kendoGrid({
       dataSource: dataSource,
       pageable: true,
       columns: [
          { field: "main", filterable: { ui:main }, title: "Main" }
          { field: "sub", filterable: { ui:sub }, title: "Sub" }
       ],
            groupable: true,
            sortable: true,
            filterable: {
                extra: false,
                operators: {
                    string: {
                        startswith: "Starts with",
                        eq: "Is equal to",
                        neq: "Is not equal to"
                    }
                }
            }
    });
    function main(element) {
        element.kendoDropDownList({
            dataSource: main,
            optionLabel: "--Select Value--"
        });
    }
    });