Category Structure

I’m currently using WordPress to setup a project which will lists jobs. The first parent categories look like this:

– All (Showing all jobs in all categories)
– Fulltime (Showing all jobs sorted as Fulltime)
– Freelance (Showing all jobs sorted as Freelance)

That is not a problem, but I have not found a solution to the next round of categories, as I will have 3-4 child categories under the three parent categories. The child categories will have the same names for all parent categories.

Example:
– ALL
– Webdesign (Showing both Fulltime & Freelance)
– Programming (Showing both Fulltime & Freelance)
– Content (Showing both Fulltime & Freelance)

– FULLTIME
– Webdesign (Showing Fulltim)
– Programming (Showing Fulltime)
– Content (Showing Fulltime)

– FREELANCE
– Webdesign (Showing Freelance)
– Programming (Showing Freelance)
– Content (Showing Freelance)

I hope you understand what I want to accomplish, some sort of child categories working for diffrent parent categories or sorting posts in Fulltime and Webdesign by something like /fulltime/webdesign/.

How should I solve this?