Forced products added by different rules are not summed

I have a webshop that sells craft beer and in my country (Estonia) we need to add the recycling fee to each sold bottle. So if I sell one bottle, I will add a forced sell of recycling fee x 1. If i sell a whole case (24), I will add recycling x 24. This all works fine and I have different rules defined for single bottles and cases. But the recycling fees are not summed together in the cart or checkout. When I add 5 single bottles, I will have one line for 5 x recycling but when I add another case to that, I will have 5 x recycling and 24 x recycling on separate lines. I would like them all to be summed together as 29 x recycling.

Hope this wasn’t too confusing.