The Create Element menu in the Model Browser allows you to group elements into categories. You can also use various menus in dialogs and specifications to group elements. Use the Category property of a customization element to create categories.
Assign the custom stereotype (in this case the «Company» stereotype) as a Customization Target property in the customization element Specification window. Specify the Package metaclass as a Possible Owners property value. Please see the Case Study: Creating Your First Customization for more details.
In the customization element Specification window:
specify the name of a new category as the Category property value (for example, Requirements).
specify the name of an element to create as the Representation text property value (for example, Business Requirements).