We would need an option to make limits by 6pcs (for example: 6,12,18,24…) In our country you could only ship drinks in glass bottles if there are 6 bottles packed in standard packaging and all 6 bottles need to be in the packaging.
With Order Minimum/Maximum Amount for WooCommerce plugin it would not be possible to achieve it. But we have another plugin, Min Max Default Quantity for WooCommerce, for this case. After installing the plugin, you would need to go the “Fixed Quantity” and enable it. Then please set the “All products” option to “6,12,18,24…”. Then finally go to the “Quantity Dropdown” section and enable it as well.
Please give it a try, let us know if you face any issues.