Locking the format of one series in a Pivot Chart in Excel 2010

I have a relatively simple pivot chart with one slicer active to allow me to re-plot the chart for that category. The main chart is a stacked bar chart with one series plotted as a line. As i change the category with the slicer and move to one which doesnt have data in all the Pivot Table categories the chart automatically re-plots but as there are fewer series it turns the line back into a stacked bar. Is there a way to lock the formatting of a series to always display as one type of chart, i.e. for my chosen series i want it always to be a line but the rest can be reformatted whenever the number of series making up the stacked bars changes?