env command doesn't work in <group if> block

edit

Hi. I'm trying to setup logger level using custom argument in launch file. But it seems doesn't work. For example here is a code below, printing Hello World, without affecting login level. Outside this block command works fine. ROS Kinetic

<group if="$(arg debug)">
    <node name="pub_text" pkg="rostopic" type="rostopic"
          args="pub /msg std_msgs/String 'Hello world'"
          output="screen" />
    <node name="print_text" pkg="rostopic" type="rostopic"
          args="echo /msg" output="screen" />

    <env name="ROSCONSOLE_CONFIG_FILE" value="$(find node_name)/config/rosconsole_debug.config"/>
</group>