I need to make use of a beta version of Xcode and so I created a second account on my machine, account B. I wish to install the beta Xcode onto account B such that account A is not able to see this application, e.g. through the open with menu, or the launchpad. Is this possible? It seems like applications are visible from all accounts whether in the Applications folder of the original user or not.
Yes, apps in /Applications are shared with all users. The standard location for apps that you only want a certain user to see is ~/Applications. You may need to create this folder if it doesn't exist—it will automatically get an icon.