save all vcf file into single one

hi
sir
we are having a issue of creating vcf file for contacts. we are creating single contact vcf using this code
MapiContact contact = new MapiContact();
                contact.NameInfo = new MapiContactNamePropertySet(firstname, middlename, Lastname);
                contact.PersonalInfo.Gender = MapiContactGender.Male;
                contact.ProfessionalInfo = new MapiContactProfessionalPropertySet(company_name, job_title);
                contact.PhysicalAddresses.WorkAddress.Address = businessAddress + businessCity + businessState;
                contact.Telephones.BusinessTelephoneNumber = mobilePhone;
                contact.Telephones.HomeTelephoneNumber = homePhone;
                contact.Save(outpath +".vcf", ContactSaveFormat.VCard);
this is the code.
but we need single vcf file for more than 1000 contacts.
thankz and regards
Mantu Malakar