Line with Totals on line chart

Hey guys,

Not sure if this is a basic questions or if it is not possible.

I have a line chart visualization that shows the count of customer accounts by Region overtime. This results in a line per region being displayed.

One request that I have from our end users is to add a line with the total numer of accounts. Is this possible? I’m not seeing how. I could have it not being aggregated by the same fields the other lines have (Region in our scenario).

Thanks in advance guys!