According to documentation for Kendo UI for Angular (https://www.telerik.com/kendo-angular-ui/components/grid/sorting/multi-sort/#toc-sort-key-modifier) there is possible to customize the multi-column sorting functionality of the grid by setting "multiSortKey" option of the "sortable" property (https://www.telerik.com/kendo-angular-ui/components/grid/api/MultipleSortSettings/#toc-multisortkey/).

Unfortunately, for KendoReact there is no such an option accessible for the "sortable" property of the data grid. We would really like to customize multi-column sorting fuctionality of our grids by the way that it is possible for Kendo UI for Angular, so we are requesting to add/make public option "multiSortKey" of the "sortable" property.