I am using a dual-arm robot with waist urdf and generating the corresponding srdf. Now I just want to plan the behavior of the single arm through the planner. The link chain to the end effector in my urdf passes through the waist link, can I not use the move group configured in the srdf to perform motion planning for the specified joint and bypass the waist link? I have tried many methods, including setting the fixed_joint_indices parameter, but the planning still includes waist joint activities. What should I do?