I'm not sure if I understand right, but I think that what you need is our premium add-on ATUM Product Levels.
With this add-on you can create raw materials or products parts, and then link them to a final product, so its stock will be composed and deducted from the raw materials our product parts.
In your case, packs would be the raw materials (with this add-on you can create several levels of raw materials if you need) and the final product would be the pallet, so you have to set that in order to create 1 pallet you will need 4 packs.
I leave you here the link to the documentation where you will find useful info about how the add-on works: https://forum.stockmanagementlabs.com/t/product-levels-documentation
And the link to the demo site in case you want to try the free trial: https://stockmanagementlabs.com/addons/atum-product-levels/
Hope this helps,