The proposition for incurring a bonded indebtedness under Section 27451 may be submitted to the voters of any public agency or portion thereof at the same election as a proposition to create the special transit service district within a public agency or portion thereof, held pursuant to Article 3 (commencing at Section 27421). In such event a proposition for incurring a bonded indebtedness shall be submitted at a separate special bond election in all portions of the special transit service district in which no election is held pursuant to Article 3 (commencing at Section 27421).