Is there a way to expand the dropdown menu content upwards?

I would like to use an accordion inside a bootstrap dropdown with up direction ("dropup") and make the menu expand upwards.

I managed to setup the "accordion" inside the dropdown as you can see in the code example.

Here is the html

<div class="dropup" id="dropdownUp">
            <button
              class="btn btn-secondary dropdown-toggle"
              type="button"
              id="btnGroup"
              data-toggle="dropdown"
              aria-haspopup="true"
              aria-expanded="false"
            >
              Dropdown
            </button>
            <div class="dropdown-menu" aria-labelledby="btnGroup" id="dmenu">
              <a class="dropdown-item keepopen" href="#c_1" data-toggle="collapse">Category 1</a>
              <ul class="collapse" id="c_1" data-parent="#dmenu">
                <li>Child 1-1</li>
                <li>Child 1-2</li>
                <li>Child 1-3</li>
              </ul>
              <a class="dropdown-item keepopen" href="#c_2" data-toggle="collapse">Category 2</a>
              <ul class="collapse" id="c_2" data-parent="#dmenu">
                <li>Child 2-1</li>
                <li>Child 2-2</li>
              </ul>
              <a class="dropdown-item keepopen" href="#c_3" data-toggle="collapse">Category 3</a>
              <ul class="collapse" id="c_3" data-parent="#dmenu">
                <li>Child 3-1</li>
              </ul>
            </div>
          </div>

And here is the javascript

$(document).ready(function() {
  $('#dropdownUp').on('hide.bs.dropdown', function(e) {
    if ($(e.clickEvent.target).hasClass('keepopen')) {
      return false;
    }
    return true;
  });

  $('#dropdownUp').on('hidden.bs.dropdown', function() {
    $('.dropdown-menu .collapse.show').collapse('hide');
  });
});

Here the link to the example

https://jsbin.com/cirejudipu/edit?html,js,output

The problem is, when the collapse expands, the dropdown menu goes over the button. Is there a way to make the accordion and the dropdown menu expand upwards? Thank you.