Gauge widget multiple / virtual datapoints and datapoint as min / max

I was looking to create a dashboard gauge widget for memory used in a cluster. But to do this I need to have multiple datapoints and virtual datapoints (so that I can create a used memory expression using ActiveReal, TotalReal, and Cached) and also so that I could use the sum on TotalReal for the max of the gauge (so that it can automatically grow as my cluster does). I would expect this to work more similar to how the pie chart widget does now (allowing multiple datasources) but maybe only allowing 1 graph item.