A method and system allows multiple and simultaneous use of a pre-paid calling card. A call management system allows for the completion of multiple calls under one pre-paid calling card account number. Depending on the number of concurrent users, a billing system assigns a portion of the total number of available service units to individualized user accounts. The individualized accounts are debited according to the rate charges for each of the calls and are initially assigned an account balance that allows all concurrent users with the same amount of talk time.