One VM per CSV?

I'm using the metric graph widget.  I can't see a way to get data from more than one VM at a time on a single CSV.  For example, CPU Demand (MHz) for vm1 and CPU Demand (MHz) for vm2 on the same csv file.   I can only download CPU Demand (MHz) for csv for one VM at a time. Two separate csv files, then have to combine them.  Is this a design limitation?  Someone please Tell me there's a better way.....