Combining multiple measured values into one graph/widget

Hi,

I will have cca 40 devices measuring roughly 4000A total in a large factory. I need to check that we do not go over specific current for licensing reasons with distributor.

I am wondering if I can have a graph displaying total consumption per production room (I have 7), and total consumption per entire factory - putting together the 40 individual devices, not by installing a 4000A measuring device, because there is no such thing.

I am sufficiently advanced in javascript to do this, but it seems I can only address the specific device by d.***. Is there an option to go deviceID.*** or deviceName.*** to make a combined graph?

If not, would it be difficult to ask for?

Thank you!