How do I stop sharing passwords between Chrome and Safari on MacBook Pro?

I shared password info between chrome and Safari when prompted with the latest update on my iPhone. My problem is I have a different username and password for a website in chrome than the same website app on my iPhone. My MacBook will not allow me to utilize the correct chrome username and password as it keeps trying to fill it with the iPhone app username and password. I'm looking for a way to undo the sharing.

[Re-Titled by Moderator]