How to make an accept condition for droppable td to accept only the class within the same row?

I have this droppable td.

$('#ScrumTable td').droppable({
    hoverClass: 'ondrop',
    accept: '.card',
    drop: function(event, ui){
        $(this).append($(ui.draggable));
        ui.draggable.css("top",$(this).css("top"))
        ui.draggable.css("left",$(this).css("left"))
        if(  parseInt( $(this).index() ) + 1 == 1){
            ui.draggable.addClass('backlog-card');
            ui.draggable.removeClass('inprogress-card');
            ui.draggable.removeClass('tovalidate-card');
        }
        else if(  parseInt( $(this).index() ) + 1 == 2){
            ui.draggable.addClass('inprogress-card');
            ui.draggable.removeClass('backlog-card');
            ui.draggable.removeClass('tovalidate-card');
        }
        else if(  parseInt( $(this).index() ) + 1 == 3){
            ui.draggable.addClass('tovalidate-card');
            ui.draggable.removeClass('inprogress-card');
            ui.draggable.removeClass('backlog-card');
        }
    }
});

The droppable td above must only accept the class that is within the same row. What condition can I put to the accept attribute of the droppable td?