Namespacing hardware_interface/PositionJointInterface for multiple robots in Gazebo

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I am trying to simulate three Universal Robot arms in Gazebo. I am using the official repo. I was able to spawn all the robots in Gazebo but the only the last robot(linked in the URDF) actually can move. After digging out for the problem, I noticed hardware_interface/PositionJointInterface is not namespaced properly. So that is the reason only the robot which is linked at the end can move. I verified by changing the position of relvant joints in the URDF.

To create the issue following steps can be followed:

mkdir -p test_ws/src && cd test_ws/src 

git clone https://github.com/ros-industrial/universal_robot/

catkin_create_pkg test_urdf

# Extract test_urdf.zip(attached to this post) to test_urdf package just created. 

cd ..

catkin_make

source devel/setup.bash

roslaunch test_urdf ur_gazebo.launch

# In another terminal 

rosrun rqt_joint_trajectory_controller rqt_joint_trajectory_controller

test_urdf.zip

Currently after executing the above mentioned launch file a gazebo world with three arms will be simulated. Now only left arm can be moved as it is linked at the the end in test_urdf/urdf/test.urdf.xacro. If another arm is taken to the last in the same URDF than that can be moved only.

The problem actually lies in defining the respective hardware_interface/PositionJointInterface which currently is the same for everyone. As can be seen in test_urdf/urdf/arms/ right, center or left arm.

Is there any way that hardware_interface/PositionJointInterface can be taken into namespaces respectively in xacro files?