Possible to sum values to create single Line in Bar Chart

[Alex Grill]

So I have a bar chart of hours per month and I am trying to show the total hours per month in relation to the Plan Hours for that month by includinga Horizontal Line. I have the chart set to Trellis by Month so we can see the Plan Hours for each individual month.

The issue comes when I want to include more than one location in a single grouping. The hours included in the Bar Chart are summed to create one bar per month. However, instead of summing the Plan Hours tocreate a new line, it just adds another line with the new additional Plan Hours value.

I do not want to use Side by Side Bars as when I include several months, it gets too crowded. I have also tried to use Shadows showing Unfiltered Data, but I have it filtered down by location and the shadows include ALL hours for ALL cities-- I don't think it's possible to have the shadow account for certain filters while ignoring others, but if that's an option I am open to it.

I would also really prefer not to use a combination chart with a line graph as the Plan Hours aren't continuous, each month is an independent value.

Any help or advice on how to effective show this data would be great. Thank you!