Assigning 2 domains to one attribute field in a feature class.

Dear Team,

I am aiming to assign 2 domains to one attribute field in a feature class.
e.g. The attribute field "Site Type" accepts the following values (Domain1):
- 'Fort'
- 'House'
- 'Tower'
Domain2 for "Site Type" would accept the following values:
The values in Domain1 +
- 'Cemetery'
- 'Settlement'
- 'Stables'

Is it possible first of all?
In other words, is there any way to perform a union between defined domains in a file geodatabase or in a Enterprise Geodatabase?
Or maybe perform parent/child relations on domains?


Please help and Thanks!