Linking back to previous webpage?

Currently the company I work for separates their company corporate website and their careers page. What this means is if you go to the parent site and click on the link to see career opportunities, you go to a completely different website. Both sites have similar designs but the navigation is different.

The problem we are having is linking back to the parent page. Currently, we are putting a link in the main nav on the careers page that says parentpage.com and from a usability perspective we don't feel that it is the best way to treat it. How can this can be solved and still be usable for our users?