Looking for something like this?
var dropped;
var titleDrop;
var titleChange;
$(function() {
$(".sortable").sortable({
items: ".sort",
stop: function( event, ui ) {
if(titleDrop != titleChange)
dropped.append(ui.item);
},
change: function(event, ui){
titleChange = ui.placeholder.parent().find('p').text();
}
});
$( ".item" ).droppable({
accept: ".sort",
drop: function( event, ui ) {
dropped = $(this);
titleDrop = $(this).find('p').text();
}
});
});
Update
Incorporates switching places: