Adding this script to your select question will move all items into the first column under specified circumstances:
<script>
$(document).ready(function(){
var count = $('input[name="hid_list_[% QuestionName() %]"]').val().split(',').length;
if (count <= 3) {
$('#[% QuestionName() %]_div .response_column:first-child').append($('#[% QuestionName() %]_div .response_row'));
$('#[% QuestionName() %]_div .response_column:not(:first-child)').remove();
}
})
</script>
Does that serve your needs?