Spawning multiples robots with 1 URDF/XACRO file

edit

Hello,

I'm spawning 2 pioneer robots but I have some plug-ins for the sensors, odom and cmd/vel that are publishing for the same topics.

Is there any simple/and efficient way to change the topics where they are publishing this messages? The robots have different names already. Anyone knows how to do this?

I don't want just to copy paste all the xacro code and change the topics by hand, I think its not a good solution.

Anyone knows how to do this? So far I created 2 launch files to try to do this:

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

    <include file="$(find gazebo_ros)/launch/empty_world.launch"/>

  <group ns="p3dx_1">
    <include file="$(find p3dx_gazebo)/launch/pioneer.launch">
      <arg name="name" value="p3dx_1"/>
      <arg name="pos_x" value="-4.0"/>
      <arg name="namespace_arg" value="p3dx_1"/>
    </include>
  </group>

  <group ns="p3dx_2">
    <include file="$(find p3dx_gazebo)/launch/pioneer.launch">
      <arg name="name" value="p3dx_2"/>
      <arg name="pos_x" value="4.0"/>
      <arg name="namespace_arg" value="p3dx_2"/>
    </include>
  </group>
</launch>

and this one:

<launch>
  <!-- push robot_description to factory and spawn robot in gazebo -->
  <arg name="name" default="pioneer"/>
  <arg name="pos_x" default="0.0"/>
  <arg name="pos_y" default="0.0"/>
  <arg name="pos_z" default="0.0"/>
  <arg name="namespace_arg" default=""/>

  <arg name="model" default="$(find p3dx_description)/urdf/$(arg namespace_arg).xacro"/>
  <!-- send the robot XML to param server -->
  <param name="robot_description" command="$(find xacro)/xacro.py '$(arg model)'" />
  <param name="tf_prefix" value="$(arg namespace_arg)" />
  <node name="spawn_robot" pkg="gazebo_ros" type="spawn_model"
        args="-param robot_description
              -urdf
              -x $(arg pos_x)
              -y $(arg pos_y)
              -z $(arg pos_z)
              -model $(arg name)"
        respawn="false" output="screen">
  </node>
</launch>

But I think this way I will have to copy the .xacro files. Anyone has a better idea?