Do we all need to visit the office?

I wonder if it is possible to have our visas for China done in Copenhagen? We are four people traveling to China and three of us are Swedish citizens, one of us has a double both Swedish and a Finnish passport (but has only collected her Finnish passport) - all four of us are living in Sweden. Is it possible if only one of us will visit your office and hand in all the passports, photos and application forms for the four of us and then collect them as well, or do we all need to go? Do you accept payment with Visa and MasterCard? Is there anything else we need to have in mind...