Unlock entities "Group Unit", "Default Unit"

Hello.

The question arose about the unlocking of the entity "Group Unit" and "Default Unit".

We have products. The products have a Unit Group.

Unit Group have Default Units.

Default Units have the Quantity.

The quantity of a Default Units depends on the product and the Quantity is not a constant.

We have many products that have the same  Default Units but different Quantity.

We need to change (choose) the number in Quantity of Default Units according to the the product. But Quantity of Default Unit is still constant.
How to unlock these entities, or how to use the CRM functionality to solve this problem.