Suppose the device A (with assigned customer) is a gateway device that creates devices B1 … Bn (with relation created) by sending their first telemetries to the server. I want B1 … Bn to be automatically assigned to customer.

I am currently experimenting with a temperature sensor. Data sent by the sensor is received by KPN Things, which will then send it to ThingsBoard (via a webhook). Such data looks like this (example taken from KPN Things documentation):