since I am out of ideas, I hope someone else has a clever solution in this matter.
I am currently working on a shop for a wine seller, and they came up with quite the complex order requirements, which read as follows:
Minimum products per order: 6 bottles
If these six bottles are composed of three or more different bottles, buyer pays full price for each of the 6 bottles.
If these six bottles are composed of 2 x 3 (and only 2 x 3*) of the same bottles, buyer receives a 20 % discount on all 6. (* If less than 3, say [1 x 4] + [1 x 2], of one of those wine is ordered, neither it nor the other gets the discount.)
Orders can also include non-wine products such as marmalade, whisky, pasta, etc.
To be honest, I don’t think this is customer-friendly at all, and I will try to convince them of an easier to understand-approach. But maybe I just haven’t found the solution that could meet these requirements.