Best practice for adding/complement additional data to existing documents

Hello there,
we're only scratched the surface regarding the possibilities in Elasticsearch so the following question/example might be pretty basic:
In our example we have multiple Hosts (VDI Workplaces) that are tied/owned by specific employees. What i want to achieve is to add the data that Employee-A owns hostname VDI-X.
I am partly into the documentation "Adding data to Elasticsearch | Elasticsearch Service Documentation | Elastic".
Hopefully anyone has some tips or advices to achieve what i've stated in the example.
Thanks in advance!