$(function(e){
var select = [ $('#select1').data('i', 0), $('#select2').data('i', 1), $('#select3').data('i', 2) ];
$('#select1, #select2, #select3').change(function(e){
var s = $(this);
var v = s.val();
for( var i = -1; select[++i]; )
if( s.data('i') !== i )
select[i].remove('option[value=' +v+ ']');
});
});