http://www.dragonair.com/ka/en_HK/ab...-requests.html
1. Who is eligible to request a seat?
The following customers can request a seat in advance
Members of The Marco Polo Club (Silver tier or above) and oneworld Ruby tier members or above
All First and Business Class passengers
Customers holding tickets on eligible fare types – Y, B, H, K, L, M, V, W, R, E
Customers requiring special services cannot request a seat online. Please raise your request at the time of booking.
I think if you check in at T-48 hours you should be able to get pairs of seats. But maybe not 5 adjacent seats.