Combine meters

[Banjer]

Recently i've added several z-wave kwh meters in my network, and i found i am missing the possibility to combine meters to get a total or average reading from a zone. Something like a kwh meter giving me the total consumption of all the meters i have in my kitchen, or an average of all the temperature sensors in my living room. I guess i could make some virtual sensors, and populate them with (LUA) scripts, but imo it would be a nice addition to the UI.