Yes, we can. There is a hook to add additional option for roles.
Code below adds “Add custom CSS” additional option. Custom CSS will be added to the backend for the selected role once you turn this option ON for it.

add_filter('ure_role_additional_options', 'ure_custom_backend_css_option', 10, 1);

function ure_custom_backend_css_option($items) {
    $item = URE_Role_Additional_Options::create_item('custom_backend_css', esc_html__('Add custom CSS', 'user-role-editor'), 'admin_init', 'ure_add_custom_backend_css');
    $items[$item->id] = $item;
    return $items;

function ure_add_custom_backend_css() {

  add_action('admin_head', 'ure_custom_backend_css');


function ure_custom_backend_css() {
      # URE custom CSS here

I set this code as a Must Use plugin for testing.