Classifieds not seperating Parent and sub categories.

I have 3 Parent categories that have simular sub categories. The subcategories show up one after the other when someone tries to list.
Exampl:
Copmuter<<<<<Sub Category
Computer<<<<<Sub Category
Computer<<<<<Sub Category
It should be more like
Service offered <<<<Parent
Computer <<<<<Sub Category
Help needed <<<<Parent
Computer <<<<<Sub Category
Temp Work <<<<Parent
Computer <<<<<Sub Category