1. Open Group Policy Editor
  2. Create a new GPO and link it to the Computers container where you want the policy to be applied
  3. Edit the newly created GPO object and navigate to:Computer Configuration | Administrative Templates | Windows Components | Internet Explorer | Internet Control Panel | Security Page
  4. In the right pane double click the Site to Zone Assignment List
  5. Click Enabled radio button and click Show
  6. Now click Add and in the first text box type the location URL of the site/page. In the lower text box type 2 as to represents Trusted Sites in Internet Explorer. Number 1 – represents Intranet zone, 3 – Internet zone and 4 – Restricted Sites.

How to add a site to the Trusted Sites using Group Policy.