Problem launching costmap_node within <group> tag

edit

This is my issue: When I launch costmap_node outside group tag all goes fine:

<launch>
   ... 
   <rosparam file="$(find vinter_utils)/launch/costmap_params.yaml" command="load" ns="costmap_node/costmap"/>
   <node name="costmap_node" type="costmap_2d_node" pkg="costmap_2d" output="screen">
      <remap from="/map" to="/intersection/map"/>
   </node>
  ...
</launch>

But when I want to launch the node within a group tag, the costmap is not published:

<launch>
   ... 
   <group ns="intersection">
      ...
      <rosparam file="$(find vinter_utils)/launch/costmap_params.yaml" command="load" ns="costmap_node/costmap"/>
      <node name="costmap_node" type="costmap_2d_node" pkg="costmap_2d" output="screen">
         <remap from="/map" to="/intersection/map"/>
      </node>
      ...
   </group>
  ...
</launch>

I guess is something related with naming but I can't figure out what is this.

This is the .yaml file:

global_frame: "/map"
robot_base_frame: "/intersection_0"
update_frequency: 5.0
publish_frequency: 5.0
obstacle_range: 10
raytrace_range: 15

inflation_radius: 0.05
robot_radius: 0.03 

observation_sources: "base_0 base_1 base_2 base_3"

#North East Base laser
base_0:
  topic: "/base_0/base_scan"
  data_type: "LaserScan"
  observation_persistence: 0.0
  clearing: true

#South East Base laser
base_1:
  topic: "base_1/base_scan"
  data_type: "LaserScan"
  observation_persistence: 0.0
  clearing: true

#South West Base laser
base_2:
  topic: "base_2/base_scan"
  data_type: "LaserScan"
  observation_persistence: 0.0
  clearing: true

#North West Base laser
base_3:
  topic: "base_3/base_scan"
  data_type: "LaserScan"
  observation_persistence: 0.0
  clearing: true

static_map: true
publish_voxel_map: true
track_unknown_space: true