Mitch,

Try using this code, but be sure to swap out the placeholder locators for your form.  

You will need to create a single line field, make it required, and then hide it with CSS.  Using CSS will still enforce the field requirement and prevent the Submit button from actually submitting the form.

$(document).ready(function() {
  var checkboxRequired = function() {
    var counter = 0;
    var inputs = $('#Field19 input'); //Checkbox Inputs - use Field - not #q19
    
    $.each(inputs, function() {
      if ($(this).is(":checked"))
        counter += 1;
    });
           
    //"counter >= 2" can be set to the number of checked checkboxes you require
    if (counter >= 2) {
      $('#Field11').val(1); //hidden, required, single line field
    } else {
      $('#Field11').val('');
    }
  };
  
  $('#q19').on('click', checkboxRequired);  //checkbox field - using q will just broaden the area on the page where the function is triggered
  
  $('.Submit').on('click', function () {
    var checkboxController = $('#Field11').val();
    if (checkboxController == "") {
      alert("You must choose two options in the checkbox field"); //you can customize the prompt here
      $('html, body').animate({
        scrollTop: $('#q19').offset().top
      }, 1000); //1000 is milliseconds for the animation - increase for a slower scroll, decrease for faster scroll
    }
  });
});