Make applications accessible to specific users? I have an "Artist" user and a "Developer" user.

I'm wondering if there is a way to make system wide applications only accessible to certain users.
For example, I would like Pixelmator to only be accessible by the "Artist" user and for XCode to only be accessible by the "Developer" user.

Is this possible? Should I just chmod o-rwx TheApplication.app and place the users and apps in specific groups?
I'm wondering whether you could just move/install the required applications to a ~/Applications directory (e.g. /Users/Artist/Applications), rather than /Applications. That way, particular applications in the local applications directory would only be available to that logged in user.

Alternatively, you could always enable Parental Controls on the "Artist" account, then restrict the set of apps that user could run. The caveat being, that user account could no longer be an administrator.