I agree with iad_nomad, there are no easy connection to PNQ from Bombay to connect to the US/European flights. One option you can consider is connecting through other indian airports. For example MAA(chennai) you can take BA to MAA which comes in at 1 AM and there is a flight to PNQ at 4.45 AM (spicejet) which would give you enough time to connect. International & domestic terminals are right next to each other in MAA.