One main DB - three sub Non-Critical DB’s over 3 levels.
One main Critical Loads DB - three sub DB’s over 3 levels.
Four homes.
It was a interesting to figure it out over a time, yes, trunking was involved in the end, but it was a big case of, "try this, lets see, try that now … " and then the penny dropped how to do it cleverly.
Experience (installers) … it goes a hell of a long way if they have done many different installations over years.
Then sometimes just plain ole “here, hold my beer, I’ve got this” brains out there who instantly split the “chaff from the corn”.
That is what happened here few weeks back. A new young electrician just “saw” a damn clever way to do it.
Less cabling, less trunking … KISS.