Creating a sum from multiple sensor values

Hi there - need some help from the experts.
I’m sure it can be done with some spiffy ‘for - endfor’ loops or something similar but I just can’t get it sorted out.

Here we go:
I have an auto-entities card that looks like this:

type: custom:auto-entities
  type: entities
  title: Electricity Use
  state_color: false
    - entity_id: sensor.sonoff*_power
    - entity_id: sensor.s31*_power
    - entity_id: sensor.*_current_consumption
    - entity_id: sensor.*_electric_consumed_w*
    - entity_id: sensor.s31*energy_power

This card shows me all the individual Wattage from each item, i.e. lights, plugs, and all such things.

I’d like to have a total of all these values without having to add them all up individually - and without having to change the formula if & when I add e.g. a new Sonoff plug into the mix.

Anybody here who can help me out?