I'm working with Odoo 11.

I'm using variants on products but for some variants, I want to have different stocks and different purchase prices from my vendors compared to others. As far as I see I set reordering rules on the product variant level (from inventory app --> inventory controll --> product variants) but vendors are set by the mother product. If I change the vendor settings for the orange variant it is changed by the other variants as well. 

What I need:

Product A, orange variant --> purchace price €300/pc, minimal order quantity is 1pcs

Product A, red or blue variant --> purchase price €400/pc, minimal order quantity is 1pc

How can I do this?