Start looking at this tool. It has some settings to limit top and/or bottom points that might do what you want.
If you still want to edit your scripts then have a look at “(09:03 Multi-axis scripting” in part 3 in the link below for how you work with multiple scripts in OFS. You need a video file but it can be anything that is longer than the script you are going to edit. Just rename the video to the script file or better, use the video that the original script is for (if you have the file available).