How to set up multiple email addresses for different departments under one Desk account?

How to set up multiple email addresses for different departments under one Desk account?

So under one company, we have multiple departments with numerous team members needing access to specific mailboxes, for example:-

Support
Accounts
Social Media
Etc

I have set up Desk (new user account) and can forward the email to the one zoho email address it has provided but how to set up others and be able to switch between mailboxes under one company login?