You should organize your agile project using three different kinds of backlog. At the highest level, you'll want a PRODUCT backlog which lists all features that are currently being considered for inclusion in a product over the course of multiple projects. Next, you'll want a PROJECT backlog that includes just the elements from the PRODUCT backlog that are being considered for the current project. Note that a project backlog may contain items from multiple, different product backlogs. Finally, you'll need several ITERATION backlogs (also called SPRINT backlogs, when using Scrum). This last type of backlog contains the list of tasks or activities that the team has identified as necessary to complete the product backlog items assigned to the current (or upcoming) iteration.