Special Portal Creation Conditions

I am making 2 mods, both adding one new dimension to a mod. The concept is simple I want to make one mod adding a new dimension, which portal can only be in Nether, and cannot be activated in any other dimension, and the second one, that can only be activated in the End with The End! Achievement obtained (kill the Ender Dragon). But when I try to use procedures, I cannot add them to the dimension's code

𝓐𝓷𝔂 𝓦𝓪𝔂 𝓸𝓯 𝓶𝓪𝓴𝓲𝓷𝓰 𝓽𝓱𝓲𝓼?