One of the more highly-voted feature requests on the HESK UserVoice (and some support on the Mods for HESK UserVoice) is the ability to create "subcategories". I'm planning on adding this into the next feature-based release of Mods for HESK (so don't expect it in a bugfix release ); however I want to run my plan by the community in case I am missing any features, or if you have any questions.
Basics
Categories can have a "parent" category, making the category a child. A category can only have one parent, but multiple categories can have the same parent.
There is no limit to the number of "levels" in category nesting (so you can have child categories, grandchild categories, etc)
Security
Users who have access to a certain category will automatically have access to its child categories (i.e. if you have a category "Billing" with subcategories "Payments" and "Refunds", if you give a user access to "Billing", they will also be able to manage tickets in the "Payments" and "Refunds" categories).
One question of mine that I want you (the community) to answer:
Should users be able to create tickets in a category if the category has subcategories? I'm thinking no at the moment as you would want your users to be as specific as possible. A "Other" subcategory could be used for tickets that may not fit into a certain set of subcategories.
Mike, Lead Developer of HESK: A surprisingly simple, user-friendly and FREE help desk software with integrated knowledgebase.
); however I want to run my plan by the community in case I am missing any features, or if you have any questions.