Given that we're holding the wedding a country we don't live in, but the majority of guests do, I was wondering whether it was acceptable to ask people to RSVP by email. I could have someone buy a sheet of international stamps, post them to me, and then send return envelopes with everything, but this ends up costing us about four times as much in postage as we'd planned (Australian postage is horrendously expensive). Alternately, I could have the RSVPs sent to a family member, but I don't know if that's asking a bit much seeing as I've already sent everyone I'm close to on at least one errand.
Advice would be much appreciated.
Thank you all very much.