same order multiple aggregated shipping fees

I’m facing a complicated issue with shipping and I’m not aware of something on the market that covers the solution.

basically my store ships 3 category of product:

• room temperature

• 4°c

  • -18°c

now, the courriers separate the 3 items when shipped and ask 3 separate shipping fees. so if a customers orders 1 4c product and 1 -18c products, he has to pay 2 shipping fees at checkout. it gets even more complicated if you consider every shipping temperature has its own threshold for free shipping, so we could have one order which reached free shipping on 1 temperature but still has to pay for shipping on the other temp product.

how would you approach such case?