Secret Seats - how to in Tessitura

Hi guys

I was wondering if any of you are offering secret seats in your organization? And if yes, how do you handle the orders in Tessitura? 

We are planning to do the following:

- On the website you are only able to select Best Seats in a specific MOS for secret Seats customers.

- The customer will not be informed where they are seated and they will not receive a PAH ticket.

- In Tessitura, the online orders are seated in Price Category E, on specific allocated seats.

- 2 days before the performance, the box office upgrade the seats by moving them to a higher Price Category if any seats are available. 

- The upgrade is handled in a new MOS and the tickets are send to the customer.

We have a couple of challenges; if two secret seats customers would like to be upgraded together, how do you handle that? 
Do any of you handle the upgrade automatically and not in the box office? 

Kind regards Louise