I confirm you can have more than one 6873 (up to 5) configured as front desk console.
All consoles (and the web application) can access to the hotel functions at the same time.
Remember that only one “user” number can be configured as “reception” number.
If the different consoles are next to each other, you can allocate them to the same “reception” number.
The phone calls to “reception” (calls from the rooms, “answer message” keys, …) will be presented (display and ringing) in parallel; once answered ringing will stop on the other.
As an alternative, you can give the other phone a different call number, and configure a BLF key of the reception number.
The calls will be presented on the “main” reception phone, and the other one will see/hear the BLF ringing. Drawback in that case is that you see the caller id only after having answered.
other alternative for the back office is to use a BLF of the reception user and the web based application to activate wake-up.