Updating Line Graph

I have used the autoshapes function to add red lines at key data points within my line graph. I was wondering if there is any way to update/add data to the graphs and still have the red lines stay where they are supposed to. Since I'm going to be updating this graph frequently, it would be a hassle to insert new lines every time the graph changes. Anyone have any suggestions?????

Without specifics of how you have the data layed out it's kind of hard to be specific. When I want to do similar things, I will usually simply add the "highlighted section" as another series. For a line chart (category type x axis), you have to set the data up so each series is plotted against the same x values, something like:

a,1
b,2,=b2
c,3,=c2
d,4
e,5

If you add column three to a line chart, it only plots the two b and c points, and you can then format the line on that series to be red. Then, as the data in column 2 is updated, the highlighted series is also updated.