Task groups are a great way to organize tasks within projects. In fact, they can be used in place of sub-projects, allowing you to reduce complex project hierarchy. Optionally, if you prefer, you can transfer your sub-projects into task groups
Option 1
If project hierarchy is working for you, it is not necessary to transition existing sub-projects into task groups. However, if you prefer, you can structure any future projects using task groups instead of sub-projects. For more information, see Create Task Groups article.
Option 2
If you want to transition your sub-projects into task groups, you can do so by adding all of the tasks within the sub-projects to task groups and then moving those task groups to the parent/master project.
Step 1
Identify or create the master project that will serve as the place where all of the tasks from the sub-projects will go. This could be the parent project in the hierarchy or it could be a completely new project.
Step 2
Organize tasks within sub-projects into task groups. This step is necessary in order to quickly move the tasks into the master project. For this purpose, it might be best to create a single task group in every sub-project and then place all of the project's tasks into it. For more information, see: Create Task Groups, Move Tasks Between Task Groups.
Step 3
Move the task groups into the master project. After you put all of the tasks from the sub-projects into task groups, you can move those task groups into the master project. You can read more about the process in the Move Tasks Between Projects article.
Step 4
Delete empty sub-projects. After you move all of the task groups from the sub-projects into the new master project, all of the empty sub-projects can be deleted.