1. A method performed by a network system, the method comprising: obtaining, from a device-group management entity, at least a portion of a bill-by-account service policy applicable to a device group managed at least in part by the device-group management entity, the device-group management entity being different from a network system operator associated with the network system, the device group including a plurality of end-user devices communicatively coupled or capable of being communicatively coupled to the network system over a wireless access network, the plurality of end-user devices including a particular end-user device, the particular end-user device identified by a particular credential differentiating the particular end-user device from all other end-user devices in the device group, the bill-by-account service policy to be applied when any end-user device in the device group communicates or attempts to communicate over the wireless access network, the bill-by-account service policy comprising: a classification policy to assist in identifying one or more bill-by-account service activities, the one or more bill-by-account service activities being a subset of all service activities available over the wireless access network, the one or more bill-by-account service activities comprising data traffic, and an accounting policy to assist in accounting for usage of the wireless access network associated with the one or more bill-by-account service activities; identifying attempted or successful wireless access network data traffic associated with the particular end-user device; based on at least a portion of the classification policy, identifying a particular service activity within the attempted or successful wireless access network data traffic associated with the particular end-user device, the particular service activity being one of the one or more bill-by-account service activities; obtaining a record comprising the particular credential and a usage measure providing an indication of a wireless access network usage associated with the particular service activity; and based on the accounting policy, allocating at least a portion of the usage measure to an account associated with an entity that is financially responsible for at least a portion of usage of the wireless access network associated with the device group.