Hi Usman,
Just a small correction, you may not need to add any new 'Data Partition Controlled Tables' as there is out of the box table already defined for pcat object i.e. Prob_Category (Request Area table).
All you need to do is create a new data partition on this table and create e new constraint as mentioned in my previous comments i.e. as below
Table Name: Prob_Category
Constraint Type: View
constraint : sym like 'Software.%'
save the above constraint and this will restrict the data partitioned selected user from viewing the sub areas apart from "Software."
Note: Need to logout and login back for the constraint to take effect.
Let me know if helped to resolved you query. If yes, Please mark it as answer correct