In our application we have a number of nodes controlling the robot and rviz config to display the state of the system. The nodes are launched by calling roslaunch/python/python-3 commands in separate terminals. some of the processes within the application are not related to ros: they are controlling the robot directly. I have the following question: could we somehow develop rviz config with custom buttons (or other elements) such that nodes and/or external processes are called via pressing these buttons in the rviz gui? Alternative solution which would also be useful: the process is launched in the terminal, however its execution is paused and waits until the button in the gui is pressed.