<table width="200" border="1">
  <tr class="tr_room_id1">
    <td colspan="2">Комната 1
      <button class="up_room" data-direction="up" data-classroom="tr_room_id1">Up</button>
      <button class="down_room" data-direction="down" data-classroom="tr_room_id1">Down</button>
    </td>
  </tr>
  <tr class="tr_room_id1">
    <td>1</td>
    <td>1</td>
  </tr>
  <tr class="tr_room_id1">
    <td>1</td>
    <td>1</td>
  </tr>
  <td colspan="2" class="tr_room_id2">Комната 2
    <button class="up_room" data-direction="up" data-classroom="tr_room_id2">Up</button>
    <button class="down_room" data-direction="down" data-classroom="tr_room_id2">Down</button>
  </td>
  </tr>
  <tr class="tr_room_id2">
    <td>2</td>
    <td>2</td>
  </tr>
  <tr class="tr_room_id2">
    <td>2</td>
    <td>2</td>
  </tr>
  <tr class="tr_room_id2">
    <td>2</td>
    <td>2</td>
  </tr>
  <tr class="tr_room_id3">
    <td colspan="2">Комната 3
      <button class="up_room" data-direction="up" data-classroom="tr_room_id3">Up</button>
      <button class="down_room" data-direction="down" data-classroom="tr_room_id3">Down</button>
    </td>
  </tr>
  <tr class="tr_room_id3">
    <td>3</td>
    <td>3</td>
  </tr>
  <tr class="tr_room_id3">
    <td>3</td>
    <td>3</td>
  </tr>
  <tr class="tr_room_id3">
    <td>3</td>
    <td>3</td>
  </tr>
  <tr class="tr_room_id4">
    <td colspan="2">Комната 4
      <button class="up_room" data-direction="up" data-classroom="tr_room_id4">Up</button>
      <button class="down_room" data-direction="down" data-classroom="tr_room_id4">Down</button>
    </td>
  </tr>
  <tr class="tr_room_id4">
    <td>4</td>
    <td>4</td>
  </tr>
  <tr class="tr_room_id4">
    <td>4</td>
    <td>4</td>
  </tr>
</table>

$(".up_room, .down_room").click(function() {
  var direction = $(this).data("direction");
  var classroom = $(this).data("classroom");
  $("." + classroom).each(function() {
    var row = $(this).closest("tr");
    var checked_length = $("." + classroom).length;
    if (direction == "up") {
      for (i = 0; i <= checked_length; i++) {
        row.insertBefore(row.prev());
      }
    }
    if (direction == "down") {
      for (i = 0; i <= checked_length; i++) {
        row.insertAfter(row.next());
      }
    }
  });
});