We use Office 365 for our Exchange/Outlook communication, and we have tried to setup the Helpdesk plugin to use different mail alias from a single office 365 shared mailbox to differentiate the redmine project an incoming issues should be assigned to.

The overall goal is to be able to use a shared 365 mailbox (e.g. "support@acme.com") for the helpdesk plugin to handle incoming and outgoing mails, while assigning extra mail alias to specific projects (e.g. "support-myproject@acme.com").
With this setup, we would communicate different mail addresses to customers for different projects, so for example one customer would send reports to "support-project1@acme.com", and another one to "support-project2@acme.com".

We must then be able to have those mails automatically map to tickets/issues in the relevant project.
Technically this should be possible using the "workflow automation rules": https://www.redmineup.com/pages/help/helpdesk/automation-rules - if (and only if) a condition to handle issues/mails depending on the "To Address" would be supported in the helpdesk plugin.