Create Project Definition and WBS Element for Grouping Element 
Prerequisites
You have created a project profile in Customizing for Project System.
Procedure
The initial screen for the project builder now appears.
The screen for the maintenance of the project definition now appears.
The overview screen for WBS elements now appears.
The maintenance screen for WBS elements now appears.
Enter the indicator 2 if you would only like to use the WBS element for materials with selected MRP groups. In this case, you have to create further grouping WBS elements.
The overview screen for WBS elements appears again.