How do you allocate shared facility costs across a park?

Measure the consumption of shared facilities such as swimming pool, laundry room or outdoor lighting separately from the dwellings, via a separate module on that connection. Multiply the measured total by your own kWh price and divide that amount according to a fixed key that you determine in advance: equally across all dwellings, by occupied nights, or by floor area or number of sleeping places. The measurement does not change, only the allocation key determines how much each unit contributes.