multiple ar.drones on tum_simulator

edit

Hello everyone. I've been trying to make the ros-gazebo simulator working with 2 or more drones, with no result. Using rostopic list, the topics appear with the right name (/ardrone/takeoff and /ardrone_2/takeoff etc.) but when I send a command, only one drones is receiving them, often with unexpected outcomes (it flies away =( ))

Here is my launch file,

<?xml version="1.0"?>

<launch>

  <!-- Start Gazebo with wg world running in (max) realtime -->
  <arg name="gui" default="true"/>

  <param name="/use_sim_time" value="true" />

  <node name="gazebo" pkg="gazebo" type="gazebo" args="$(find cvg_sim_gazebo)/worlds/3boxes_room.world" respawn="false" output="screen"/>
    <!-- start gui -->
  <group if="$(arg gui)">
    <node name="gazebo_gui" pkg="gazebo" type="gui" respawn="false" output="screen" required="true"/>
  </group>

  <group ns="ardrone">
  <!-- Spawn simulated quadrotor uav -->
  <include file="$(find cvg_sim_gazebo)/launch/spawn_quadrotor_classic.launch" >
    <arg name="model" value="$(find cvg_sim_gazebo)/urdf/quadrotor_sensors.urdf.xacro"/>
    <arg name="init_pose" value="-x 0 -y 0 -z 0.5"
  </include>
  </group>

  <group ns="ardrone_2">
  <!-- Spawn simulated quadrotor uav -->
  <include file="$(find cvg_sim_gazebo)/launch/spawn_quadrotor_classic.launch" >
    <arg name="model" value="$(find cvg_sim_gazebo)/urdf/quadrotor_sensors.urdf.xacro"/>
    <arg name="init_pose" value="-x 1 -y 0 -z 0.5"
  </include>
  </group>

</launch>

while the spawn_quadrotor_classic launch file is,

 <launch>
   <arg name="model" default="$(find cvg_sim_gazebo)/urdf/quadrotor.urdf.xacro"/>
   <arg name="init_pose" />
   <!-- send the robot XML to param server -->
   <param name="robot_description" command="$(find xacro)/xacro.py '$(arg model)'" />

   <!-- push robot_description to factory and spawn robot in gazebo -->
   <node name="spawn_robot" pkg="gazebo" type="spawn_model"
   args="-param robot_description
   -urdf
   $(arg init_pose)
   -model quadrotor"
     respawn="false" output="screen"/>

   <!-- start robot state publisher -->
   <node pkg="robot_state_publisher" type="state_publisher" name="robot_state_publisher" output="screen" >
     <param name="publish_frequency" type="double" value="50.0" />
     <param name="tf_prefix" type="string" value="" />
   </node>

   <node name="ground_truth_to_tf" pkg="message_to_tf" type="message_to_tf" output="screen">
     <param name="odometry_topic" value="ground_truth/state" />
     <param name="frame_id" value="nav" />
   </node>
   <!-- node name="hector_pose_estimation" pkg="hector_pose_estimation" type="hector_pose_estimation_node" output="screen"/-->

 </launch>

Any help would be appreciated! Thank you!