I have 17people who request an airport transfer from Kowloon area to hong kong airport at about 4am.

As you are such a large group, I suggest you ask your hotel to help you rent a coach for an easy travel! If you wanna use public transportation, I wonder whether u are leaving from Kowloon Station. If so, walk from where you are to Western Harbour Crossing Toll Plaza to take bus no. N962 to get off at Macau Ferry, Connaught Road Central and then transfer to bus no. N11 to HKIA.