Using multiple controller within in one MoveIt move group

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Is it possible to use different controllers for joints in the same move group with MoveIt?

I expected it to be relatively straight forward by adding another controller to the ros_controllers.yaml in the MoveIt config like this:

controller_list:
  - name: hebi_arm_controller
    action_ns: follow_joint_trajectory
    default: True
    type: FollowJointTrajectory
    joints:
      - Arm/J1_shoulder
      - Arm/J2_elbow
      - Arm/J3_wrist
  - name: rail_controller
    action_ns: follow_joint_trajectory
    default: True
    type: FollowJointTrajectory
    joints:
       - prismatic

And starting the fitting ros_control node in the launch file. However, I get the following error message:

[ERROR] [1584639200.521661239, 22.133000000] [/move_group] [ros.moveit_simple_controller_manager.ActionBasedController]: Action client not connected: rail_controller/follow_joint_trajectory

The ros topic /rail_controller/follow_joint_trajectory/* is listed when I run rostopic list. Not sure what's missing.