How to restrict items to be ordered with some fixed quantity

Hi All

We have a requirement to orter some items with some fixed quantity. For eg..we store some liquid items in containers of 5 litres(So, i container = 5 Litre). But we have a UOM conversion of 1 Litre = 1 EA. But we cannot sell 2 Litre of this item.

So, we want to add these kind of restriction where if we create any Sales Orders with these items, it should not allow me to order less than 5EA or 5 Litre or 1 Container.

How to apply such restrictions on items - can we do by utilizing any standard functionality Dual UOM feature

Thanks