Kill roscore and all nodes when rosbag play finishes?

Hello, I'm writing some automated test scripts. I'd like to run a launch script with a bag file, which works fine. But when the rosbag play completes I would like roslaunch to exit so my script can load up a new bag file and rerun roslaunch with the test.launch file. Is there an elegant way to cause all ros nodes and roscore to exit when a bag file is finished? I was thinking of making another script to monitor when rosbag finished and then execute a rosnode kill, but I thought there might be a better way. Thanks, Jason