Different submenus on different pages

Hi, I just started using wordpress to create website, thus I’m not very good at it. Here’s one of the problem I am facing currently.

I want to create different side bar menu on different pages of my website. For example, I have these 2 categories in my website: Brand Products and Equipments. Each categories have their own submenus. However, i would like to display all these submenu on their left side bar.

I understand that using widgets would be able to solve this. But this would create a same menu for both of my categories (Brand Products, Equipements). I would want one submenu on Brand Products and a different submenu on Equipments.

How am i supposed to do this?