Packaging weight that increases depending on how many items bought

[Accounts]

Say there's an item that weighs 100g.

 

If I order under 4 then the packaging weight for the whole package is 170g.

 

So if I order 3, it would be 300g + 170g.

 

However if I wish to order 6, a larger package will be needed that weighs 250g.

 

So if I order 6, it would be 600g + 250g.

 

 

I was wondering if this is possible in any way? Or if there is a work around? I could just divide 250g by 4 and then add it onto the 100g so it weighs 163g each, but I'd like to know if it's possible without having to do this.

 

Cheers