I am Dr. Prasad Akole (Critical Care Expert- http://bit.ly/Dr-Prasad-Akole) and am glad to address to your query here.
Bombay blood group
is rare and needs a special antigen test to be done.
It can be performed in big standard blood banks.
I hope you are fully satisfied with the guidance I gave.
I would be glad to answer any further queries. Please ask for any clarifications before closing and rating this answer.
Thank you and Good luck!