How can I find the implementation details of move_group.pick("object", grasps) function

[He11oworldd]

I really like the design ideas of moveit_msgs/Grasps, especially the grasp_pose, pre_grasp_approach, post_grasp_retreat and other designs. But unfortunately moveit_msgs/Grasps is not completely suitable for me. I need to improve it because my end effector is not a gripper, but a suction pump. So I want to find the implementation details of the move_group.pick("object", grasps) function.
If I design another msg type, named "mymsg". It only contains grasp_pose, pre_grasp_approach, post_grasp_retreat. Is this solution feasible?