Hide line and legend when data not present
 

I have a line graph with five lines on it. The graph looks at a range of cells for the data to graph for each of these lines. This range of cells are populated with data depending which of 52 different data set the person wishes to look at. However, not all data sets have data for all the lines, therefore some graphs actually only need two to five of the lines to be populated. I have it set up such that the line doesn't show, but the legend remains for all five lines regardless of whether data is present. How can I go about making the legend populated only when there is data present for that line? Thanks.