A web-based system, method and program product are provided for adding content to a content object stored (e.g., a custom compilation or prepublished work) in a data repository as a group of hierarchically related content entities. Each noncontainer content object is preferably stored as a separate entity in the data repository. Each content entity is also stored as a row in a digital library index class as a collection of attributes and references to related content entities and containers. As the user selects desired objects for inclusion in a content object, the system arranges the objects hierarchically, e.g., into volumes, chapters and sections according to the order specified by the user. The system then creates a file object (e.g., a CBO) defining the content object that contains a list or outline of the container and noncontainer entities selected, their identifiers, order and structure. This file object is stored separately in the data repository. An aspect of the invention is to provide permission checking. Occasionally, it may be desired to prevent certain content entities from appearing a same compilation as other content entities. For example, an author may specify that his work can not be published in the same compilation as the work of another author. Permission checking first requires associating each container and noncontainer with any mutually exclusive containers or noncontainers. For example, such association may be achieved by defining a set of rules specifying containers and/or content entities that are mutually exclusive. Upon selection of a container or noncontainer to add to the compilation, the permission checking procedure determines if the container or noncontainer is mutually exclusive of any other containers or content objects, e.g., by consulting the rules. If so, the permission checking procedure then analyzes the compilation outline to determine whether any of the other mutually exclusive containers or noncontainers already exists in the compilation. If so, then the selected container or noncontainer is not added to the compilation and the user is notified that the content selected may not be included in the compilation. Otherwise, the content is added.