Exchange 2003 physical to virtual

Hi all,

Currently: 2 Front End Exchange 2003 servers and 2 Back End Exchange 2003 servers, forming an Active/Passive Cluster. All servers are physical.

Our goal: Virtualize Exchange 2003 platform, creating new Exchange 2003 servers and remove physical servers.

We know that Exchange 2003 is too old and is out of support, and so on.... Also, use P2V method is no accepted.

The main question: Do we need to create a new Exchange cluster (supported by virtual Exchange 2003 Back-Ends) and migrate users mailboxes to this cluster or can we reuse the existing cluster whitout the need to move users mailboxes??

Thanks