The present invention relates to electronic purse systems, and in particular it relates to the improved management of multiple money flows in such systems. According to the basic principles of the present invention it is proposed that the secure access modules (SAMs) of a purse provider support multiple user groups or environments in the system while still requiring only one system key. The user groups or environments are identified by a so-called float ID tag which is advantageously added to each set of data involved in a load or purchase process performed by the user of the electronic purse system.