Zoho Desk : Sub Category should allow validation from Main Category

Zoho Desk : Sub Category should allow validation from Main Category

Hello Experts,

I am trying to use Category & Sub Category fields available in Ticket form.

I need Validation in Sub Category (derived from Main Category)

For E.G.

When we select Hardware in Main Category Then Sub Category should show 3 problems

When we select Network in Main Category Then Sub Category should show 2 Option

How to achieve this?

Regards, Vishal Kambare