The disclosed technique enables a consumer who uses a payment object to pay for goods or services to specify, by using a mobile device, how the transaction amount should be apportioned among multiple payers. In certain embodiments, the technique involves communication between a mobile payment application installed on the consumer's mobile device and a remote payment service system (PSS). The mobile payment application enables the user to specify how many payers there are, who the payers are, and exactly how the transaction amount should be apportioned among the payers. The mobile payment application communicates this information to the PSS, which then executes or triggers reimbursement to carry out the specified apportionment.