Can we Consolidate Fusion Domains into one single IAM domain?

Summary:

We have multiple delivered domains attached to our HCM/ERP fusion applications. These domains are DEV1, DEV2, TEST, and PROD.

There is a separate new domain called COMPANYNAME that we would like to use to consolidate authentication and manage all of the permissions for users through.

Is it possible to consolidate the 4 domains to be under one managed umbrella and then DELETE the old domains?

Content (required):

Consolidating Fusion domains into a single IAM domain.

Version (include the version you are using, if applicable):

Cloud Fusion HCM

Cloud Fusion ERP

Cloud Fusion SCM

Cloud Fusion EPM (Separate Tenancy)

Cloud IAM