Hike now allows you to display multiples of the same product as different line items in the cart rather than as a group. Your staff can use it to set different discounts to the same product in a sale. 

Firstly, you would need to navigate to “General” within the “Store setup” tab:

Once there, you should be able to select the “In cart, if more than 1 of a same item, display individually as separate line items” setting within the General Rules section:

Once the option has been selected, please save your changes.

Now the option has been applied to your store, you should be able to add the same product into a new sale but they should now be appearing as separate items, as shown below:

Please note: if you still want to group some of them, please click on the line item and change the product quantity there. The operation will change the quantity of a particular line item, rather adding a new one.