There is no internal contact indormation for HR business partners listed for groups inside the company. So if you want to speak with one you have to ask your manager or skip level manager for the name of the person.
I know why. They intentionally force you to speak with management about finding out who is that person so they will be alerted that you're going to HR. Of course the HR person will contact the manager and they will use any information against you. But you would never go to HR period for personnel issues because they protect the management who are proxies for the company.
This is called "catch and ki-l." It's deviant.