I need a ekstra step to the checkout

Hey

I need to add a extra step to the checkout section, that allows the customer to choose which shop he want to get his shipment from. For example:

Step 3:
Choose which shop:
1. Nearst 0$
2. Shop1 15$
3. Shop2 10$ (Popular)
4. Shop3 0.5$

-- the list of the shops have to come in a dropdown menu. Is that something you can help me with?
I think it have to be an extension but you don’t know.