appending to the task bar


I was wondering if it’s possible with the gantt to append an extra ‘bar’ to the beginning of a taskbar. For me this block would represent the time it takes getting to the next task. I don’t want to modify the existing task or its time at all, just stick an extra block in front of it with some sort of styled ‘block’. Any help you can give would be appreciated.

please check this article
you can add these bars the very same way the baselines are added in the article