You could create a "Symmetry" configuration in your "Part 1" with a Symmetry function from "Function 7" by removing the following functions, and create your "Part 2" with a part derived from "Part 1" in its "Symmetry" configuration.
After doing function 7, you symmetrize your piece by breaking the links with the first one. On the other hand, if you modify the 1 it doesn't change the 2 anymore.
On the other hand, I don't really see the point, unless it's a multi-body piece.
Like everyone else, creating a configue seems correct to me. But you can also classify the functions of your symmetry part in a folder to separate the functions used between the 2 parts, and have a more readable tree.