We don't. The two names receive roughly equal stress normally. We can of course stress one if we need to:
You met John Parker yesterday. This is Peter Parker.
I'd like to introduce you to Peter Postule and Peter Parker.The same thing applies - they normally receive the same stress.But my question to you is what if the person has a middle name like , William Jefferson Clinton? Should we stress the middle-name as well?
ps. You'll see that I changed the font size in your post. Some of us are not as young as we used to be, and can't read small fonts any more.