Group Y hierarchy

Question

I'm using the Graph Builder heat map to visualize fryer usage at several fast-food restaurants.  I'd like the graphs to be grouped in a hierarchy with Store Name -> Fryer ID -> Date as my Y Groups.  The X axis is time of day, and the Color is kW.  So each row is a day with 15 minute readings of fryer energy consumption.

When I try to make the Store->Fryer->Date hierarchy, instead of just showing the fryers that belong to a particular store, all fryers are included from all stores, and this leaves large blank sections in the graph (since there is no data at that intersection of Fryer ID and Store.)

Here is the result with JUST meter ID and Date as Y Groups:

And here is what happens when I include store number:

Can anyone think of a way to transform the data or change the hierarchy structure  to eliminate the blank rows, or do I need to construct the view with multiple graph builders?

XanGregg · Accepted Answer

Try putting the hierarchy on the Y axis as nested variables. The hierarchy there supports sparse structures.

Another option is to concatenate the variables into one variable and use that for grouping.