Exchange Archiving help needed

I've been tasked with Archiving the email of the CEO and CFO. Their mailboxes are the only 2 that will be archived. We have 2000 mailboxes, but again only 2 will ever be archived per policy.

Following is the directive and info given.

1) it must be automated, they will not be allowed or required for them to touch it at all. unless it's to retrieve email.
2) Exchange 2013, on premise. VM Boxes in a DAG config (This is the product we use)
3) Outlook 2012 standard at the desktop (This is the product we use)
4) Did I mention automated with no intervention and ONLY for 2 mailboxes
5) At this point cost wasn't thrown in the mix, but it's only for 2 mailboxes, so we can't go overboard

1) Use basic .pst archiving setup within Outlook


Any help will be appreciated...hot topic