You are right Pascal, it's not so clear.
It can be any combination of wines, but in multiple of 6.
As an examlpe:
1 x Taurasi
3 x Aglianico
2 x Greco
1 x Fiano
5 x Coda di Volpe
That's 12 bottle, 6 + 6 and it's correct
If it would be:
1 x Taurasi
3 x Aglianico
2 x Greco
1 x Fiano
it is 7 bottles, 6 + 1 and the system should ask the customer to remove 1 or add 5
Is there any easy way to achive it?
Thanks