Q: Help with drop down menus

Hello

I'm making a crocery list spreadsheet in Numbers and I have some nice ideas. I just began working with numbers and had never used programs like excel for over 3 years.

I have 6 rows and 2 sheets in my document

Rows: 1a-Kind of shop  2b-Priority  3c-Product description  4d-Quantity  5e-Max prices  6f-Total of the quantity of the product

Sheets: A-Grocery list  B-Database

1a: Dropdown menu - /Supermarket/PetShop/ToolShop/Bakkery/ElectroShop/

2b: Rating cell

3c: Dropdown menu - Variable lists

4d: Stepcounter cell - Goes up and down by quantity of "1"

5e: Value cell

6f: Value cell - 4d*5e

What I want it to do is (Numberlist = The steps that you have to take / Sublist = Information on what happens when the action is done):

As example I'm going to enlist some products into my spreadsheet for the "PetShop" and at the end of my post I'm going to list up the different tables in de Database sheet and their values.

1: You choose your Kind of shop "1a" for example PetShop

     * Cells in collum 3c show dropdown menu with data from "PetShopProductList" in Database sheet

2: In collum 3c you choose a product "ex.: Dog Biscuits" from the dropdown menu

     * Cells in 5e collum retrieve data from "PetShopProductList" in Database sheet and show the price for the right product   

3: Choose the priority from the 5 star selector, in collum 2b, for your product, if its urgent 5 stars, if not 1

4: Choose your quantity in collum 4d

     * The price from collum 5e multiplies with the quantity from collum 4d and shows in collum 6f

The thing now is, I use the PetShop as an example but here's the thing I'm stuck on:

- when your grocery list is finished, and you choose a different Kind of shop in 1a, I want the collum cells from 3c(below the previous list of PetShop) to show data in a dropdown menu retrieving data from another table in sheet Database.

For example:

- My PetShop list is finished and I choose "Bakkery" in "1a"

- Collum 3c shows a dropdown menu with data from "BakkeryProductList" instead of the one from the PetShop

- Also the previous dropdown menu's above, from the PetShop list, may not be deleted, the entered data must remain.

Thank you in advance