Been searching a bit but not found what im looking for.

What I want to do is to change so I can have different users running different parts of oracle.

For example I would like to make a user to be the one running the listener processes. This way i could remove write rights for this one. I would like to have one running the core oracle processes. And so on.

So what I wonder is if this is possible. I understand that some changing to the rights on some directories might be neccessary.

And pointers or advice are very appreciated!