I’m making a process map of my team’s processes and want to include demarcation lines at 6 weeks until launch, 5 weeks until launch etc. This is a pretty bulky map, so I want the lines to span the whole board vertically and also to be fixed in place relative to certain processes (i.e. a deal is signed and then that sets off a 6 week process, so ideally any time I move around the “deal signed” box, I want the line to move with it).  I’m currently having to keep moving the lines around and make them taller and taller.  

Is there a way to more easily integrate this “timeline” into my flowchart?