Mark a gameobject with an already created Prefab

So, assume you have 2 gameobjects in the scene, they have the same internal-hierarchy, same scripts, etc, BUT the public parameters are TOTALLY different.

If you decide to make a prefab of the gameobject, say, the object 1, how do you mark the second object to be the same prefab as object 1, (without loosing the setup of the second object) ?

I know that, one can just remove the second object, create a copy of the prefab, and change all the public parameters again... but, this is a costly and time-consuming process (to change all the public parameters again).

Does Unity offers any better way?

Thanks.