Multi email acounts/domains

We are a Zoho One customers, and all our users are set-up to send/receive email via our domain/IMAP, which we can see in CRM. All good!

We also have a separate lead gen website with a different domain. How can I set-up Zoho One/IMAP/CRM to send/receive from this domain too?

In short: How do I set-up a user to be able to send/receive in Zoho One/CRM using two different email addresses/domains?