I need someone to create an Amazon listing with variations

I am wanting to create a single listing on Amazon with 4 variations...sample, 1-pack, 2-pack & a 3-pack. I also want all 4 to be purchased FBA unless Amazon are out of stock when it reverts to MFN. Is this possible? I know the FBA & MFN items need to have different SKUs but should they have the same ASINs? I've tried following Amazon's instructions but without success so is there anyone out there that can set up the appropriate variations for me? I am the manufacturer and the only Amazon seller.