Dynamic X-Axis Constant line Small Multiples

I have a Small Multiple Stacked Bar Chart that show the grades of multiple schools. School A, School B etc. I am trying to add an x-axis constant vertical line which displays the standard deviation for each respective school. Below is what the table containing my data looks like:

If I add a constant line based on STDev, it sums the STDev and adds the same line to all Schools in the chart. Whereas I would like for it to plot the dashed vertical line for each schools STDev value rather than sum them all. Is this possible with small multiples chart?