You can create an association between a lowest task and a project or between a lowest task and a task within another project. This association is for informational purposes only.
You create associations for lowest level tasks using the Associated Project Name and Associated Task Name fields on the Setup subtab of the Task Details page. Use the Associated Project Name field to create a simple task-to-project association. If you want to create a task-to-task association, you must first enter the name of the project to which the associated task belongs, and then enter the associated task name. The prompt for the Associated Task Name field only shows published tasks for the project name that you have chosen
After you create a task association, users with view access to the task can use the Associated Project Name and Associated Task Name fields to navigate to the associated project or task. If you click on an Associated Name link, the system displays the Project Overview page for the associated project. If you click on an Associated Task Name link, the system displays the Task Overview page for the associated task. There are no links back from the destination project or task to the original task.
When you delete an associated project or task, the system deletes associations with the project or task.