Hierarchies in dimensional model

How do you handle hierarchies when each of the attributes are participating in different business processes? So for example , suppose the category (class description), subcategory (subclass description) attributes have been denormalized into the product dimension, which participates in one of the process. And suppose there is a another process where granularity is at , say category level. In that case should there be separate dimensions for category and product, with the category key placed in product dimension?

Very common scenario, you would create a conformed dimension called 'category'. The other flatened dimension, product, also stays.
This is discussed under 'conformed dimensions' topic in Kimball's DM book.