Multi pass aggregation help

Hello! I've been asked for an Analytics dashboard on how many people attended our museum over Memorial Day weekend (Fri-Sun) each year. I have it set up as a pivot table for each year with the three days broken out and then totaled. But I'm thinking that there must be a way with multi pass aggregation to do this as a column chart with each three-day block as a single column, but I don't even know where to start. Has anyone done something like this?

Thanks!

Anne Robichaux
CRM Administrator
The Historic New Orleans Collection