Talk to your airlines before you book tickets. I suppose you could book from anywhere, however there are restrictions around layover if you are coming from India (for e.g) irrespective of your nationality.Does one need to buy direct tickets from coutry of residence?
Flights with layovers not allowed?
Coming from India, you cannot stopover in say Singapore. Your flight can stop for a refuel, but you cannot disembark or change flights.