Minimum order quantity

Can we have a minimum order quantity option based on quantity added to the cart/shopping basket?

As an embroidery business I want customers to order a minimum of say 6 items of mixed products - I don't care what they are if they have the same logo applied.

The only option currently is to add minimum order quantity at SKU level which is not good - if you are a small Start-Up Business you might want to order for example 3 polo shirt, 2 hoodies and a jacket therefore shopping basket is 6 items - I don't want to make them order 6 of each

In todays market place we must be flexible to customer needs not just ours!