Keep naming conventions boring and consistent
If one domain uses hello@ for first-contact mail, the others should probably do the same. Consistent prefixes reduce internal confusion and make routing rules easier to understand, document, and change later.
The goal is not creativity. The goal is predictability. When the business grows, a simple naming pattern saves far more time than a clever one.
Route by ownership, not by archive
Many teams try to solve multi-domain email by dumping everything into one giant shared mailbox. That often makes search, triage, and accountability worse.
A better approach is to keep the visible addresses distinct while routing each one to the person or inbox that should handle it. The workflow can stay unified without collapsing every thread into one messy archive.
Treat reply identity as a safety rule
The most embarrassing failure mode is replying from the wrong address. That problem should not depend on operator memory, especially when one person handles mail for multiple brands or functions.
Your setup should make the correct sender obvious or restore it automatically. If the system cannot confirm the right sender context, it should err on the side of caution instead of guessing.
Design for handoffs before you need them
Projects change owners, clients move between team members, and staff eventually leave. Routing should be easy to reassign without migrating an entire mailbox account or handing over years of unrelated history.
The best multi-domain setup makes address ownership flexible. A visible address can move to a new operator quickly while the daily workflow stays stable for everyone else.