Strapi Dynamic Component - group by selected categories

I'm trying to build a strapi component which would render items grouped by category. What I actually try:

Having Meals grouped by different categories I want to have a list as it follows:

MealCategory_1:
  - Meal1
  - Meal2
MealCategory_2:
  - Meal1
  - Meal4
  - Meal5

So for now I have a component where I can select multiple Categories which should fetch related meals

What should I override in controller to have the desired result?