do you have a picture of what you have/need?
You could change the line to "gant bars" or "circles", but I do not believe that is what you are asking for.
You could also try getting "fancy" with having a constant/reference line and perhaps assign it to the value of what you are trying to graph.
I'm unsure of why this would be a requirement, though. Could you give a brief explanation of why this needs to be done and there may be a better way of visualizing your requirement?
The requirement let say be: I have to show Sales & Profit for each customer in a chart. Sales would be bars and Profit would be line. So i made dual axis chart. But now the line which represents Profit needs to be little different than the regular line like dashed line or dotted line.
I tried using reference line scoped for each cell but the lines don't get connected to each other which is not acceptable.