Wordpress functions to gather store hours and group them according to hours, then output the results as a list, with an optional parameter for class name.

store_hours.php

function get_hours_array() {
  $shop_hours_array = array();

  if (have_rows('hours') ) {
    while (have_rows('hours') ) {
      the_row();

      $shop_hours_array[get_sub_field('acf_fc_layout')] = array(
        'open' => get_sub_field('open_time'), 
        'close' => get_sub_field('close_time')
      );
    }
  }

  return $shop_hours_array;
}

function get_formatted_shop_hours() {

  $shop_hours = get_hours_array();
  $joined_hours = array();
  $i = 0;
  
  foreach ($shop_hours as $key => $item) {

    $day_hours = array($item['open'], $item['close']);

    if (empty($joined_hours)) { 
      $joined_hours[$i] = array($key => $day_hours);
    } else {
      $last_hours = $joined_hours[$i][$keyname];

      if ($last_hours === $day_hours) {
        $joined_hours[$i][$key] = $day_hours;
      } else {
        $i++;
        $joined_hours[$i][$key] = $day_hours;
      }
    }

    $keyname = $key;
  }

  return $joined_hours;
}

function output_shop_hours($class = null) {
  $hours = get_formatted_shop_hours();

  echo '<ul class="hour-list ' . $class . '">'; 

  foreach($hours as $hour) {
    $day = '<span class="day">' . substr(key($hour), 0, 3) . '</span>';

    if (count($hour) > 1) {
      $last_day = key( array_slice( $hour, -1, 1, TRUE) );
      $day .= ' - ' . '<span>' . substr($last_day, 0, 3) . '</span>';
    }

    echo '<li class="days">' . $day . ':</li><li class="hours">' . $hour[key($hour)][0] . ' - ' . $hour[key($hour)][1] . '</li>';
  }

  echo '</ul>';
}