1. Specify that only members of the Internal User and Portal groups should have access to the Shop Menu, by adding the groups to the Menu like this:

2. Specify that only members of the Internal User and Portal groups should have access to the content of the SHOP page, by adding the groups tag to line 2 like this:

You would get to this screen by navigating to the Shop Page on the website and clicking Customize --> HTML/CSS/JS Editor