Stewart Platform: how can i connect multiple joints to the same child link

Hi, I think my problem is similar to this post already posted in 2015 here is the [link ](https://answers.ros.org/question/216101/stewart-platform-how-can-i-connect-multiple-joints-to-the-same-child-link-but-different-parent-links/) I want to simulate a robot in Gazebo. This robot contains a kind of delta machine. It consists in : • three cylinders, • three conrods, linked with the pistons rods (tige_verin) on one side and with one plate (plate_camera_support) on the other side, • a plate (plate_camera_support). My objective is to control the altitude and the orientation of the plate (plate_camera_support) around the X axis and Y axis.  Here is the tf_tree of my URDF model. But unfortunately, I’m not able to introduce the last 2 joints of the model (in red on the picture below). Is the last answer still relevant? Is there a trick to face this « problem » ?  PS: I’m working on Ubuntu 16.04 LTS and ROS Kinetic. Thanks in Advance