What I am trying to do is when a select box is changed, another group of selects are updated.

The bit I'm having trouble with it to get some of the selects to have the same options, though not all as there will 3 lots of selects, 1 called user which calls the change on the other two sets of selects - rec & send, both of which can have any number of actual selects

So far I get change them manually, but since there isn't going to be a set amount, the user can add more as they need it's not the best solution

This is what I have so far ( the rec selects )

Code:
$('#user').on('change', function() {
  $('#rec1').empty()
  $('#rec1').load("ajax.php?action=userCardList&user=" + $("#user").val())
  $('#rec2').empty()
  $('#rec2').load("ajax.php?action=userCardList&user=" + $("#user").val())
});
Once the form is submitted, they need to be sent through to another script, something along the lines of

Code:
$.get("ajax.php?action=tradeRequest&rec=" + $( "#rec1" ).val() + "," + $( "#rec2" ).val(), function(data, status) {