A system for generating a schedule for use in triggering transmission of message content in a telecommunications network is provided. The system comprises a store for storing profiles of a plurality of recipients, and a plurality of message delivery campaigns with one or more criteria. The campaigns to be executed in relation to a given inventory, which may relate to a predetermined time period, may be arranged into one or more campaign clusters. A suitable allocation method may be used individually for each of said plurality of campaign clusters to allocate, among the plurality of recipients, target recipients for each of the campaign clusters based on campaign criteria and the profiles. The allocation process may be repeated to obtain, for example as high a number of messages as possible with the network resources available without exceeding a predetermined maximum number of messages per any given recipient. After the allocation process is completed, the campaign messages are delivered to the allocated target recipients via a communications network.