I see. So is it possible that I can separate the red line from the event but red line will still associate with the event?
Therefore, the red lines will not overlap on the other events but each red line still will go with its own event.
I draw a pic to show you and hope it'll help.
In the pic, the rea line will be z-index 0 and the other 2 events are z-index 1 and z-index 2.
If possible, can z-index-0 is an object that separate from z-index 1 and z-index 2 but each line (z-index 0 ) will be associated with z-index 1 and z-index 2.
So no matter where z-index 1 moves, z-index 0 will go with it. I hope it helps and if you have any question, please do not hesitate to let me know. Thanks.