Typically, it would be 2 breakfast to a room, regardless of guests.

Ran into a similar situation when traveling to another Hilton in another country and got clarification from the hotel.We booked two rooms, for a party of five. Each room is registered to a Gold member, so we got 2 breakfasts for each room (not # of guests).

Pretty sure that's the case for most hotels, but best to check with the hotel directly. I certainly wouldn't expect it in any case. Good luck!