JQGRID searchoptions multiselect with input field

Question

Good days. I have:

{
                    name: 'resellerDesc',
                    index: 'resellerDesc',
                    label: 'Supplier',
                    align: 'left',
                    width: 80,
                    height: 100,
                    editable: false,
                    formoptions: {
                        elmsuffix: '<font color="red">*</font>'
                    },
                    edittype: 'select',
                    search: true,
                    stype: 'select',
                    surl: '@Url.Content("~/Home/ResellerSelectDesc")',
                    searchoptions: {
                        sopt: ["in"],
                        searchOperators: false,
                        clearSearch: false,
                        dataUrl: '@Url.Content("~/Home/ResellerSelectDesc")',
                        dataInit: dataInitMultiselect,
                        attr: { multiple: "multiple", size: 4 },
                        defaultValue: getValueoffilter(filters, "resellerDesc")
                    },
                    editoptions: {
                        dataUrl: '@Url.Content("~/Home/ResellerSelect")'
                    },
                    sortable: true
                },

How to modify the serachoptions to allow input field in the multiselect drop down for Jqgrid search toolbar?

I want to achieve something like this:- https://www.cssscript.com/demo/filterable-checkable-multi-select/

Select 2 [ You can type "au" here ] then dropdown list only show audit & Renault options for dropdown to select.

Please advise.

Thanks.

Regards, Micheale