Help : How to transform a .obj file to transform it like a .pk2 or a .env file ?

I have a file in .obj and I want to enter this object into Creo, who runs with .pk2 or .env file . So, I wanna know if its possible to find a program that convert .obj file to .pk2 file. I try to find one on Google, but I don't find what I want. If you could help me, I will be so happy !!!