Hi Everyone!

I am not sure if I am posting this in the correct place, if I am not please redirect me to where I should be asking this question...

My wife and I are planning to travel on a 12 hour journey with our two boys. They are twins and 6-months-old. When booking the reservation we requested the bulkhead so we can have access to bassinets. We are flying on a Boeing 777 with United. We did not pay extra for the bulkhead seats, they were given to us because the customer service rep was empathetic to our situation. We are set to sit in seats 16E and 16D with the infants on our lap. The plane we are flying has this configuration: http://www.seatguru.com/airlines/Uni..._777-200_6.php

Today, I called to check in on our reservation and was told that there are only four oxygen masks for each group of three seats. Since having the twins on our lap would mean that there would be five people in the row, the airline will not let us sit next to each other.

My question(s):
Does anyone have any experience on this issue?
Is the airline likely to be strict on this issue?
I will try to get whoever is in 16C to switch with me in the seat of 16E so my wife and I can sit across the row from each other - what are good convincing tactics? If money is a good bribe - what would be considered appropriate?

Thanks in advance!
Mo