iWork installed from the retail box or the downloaded trial does put the three apps in a single iWork folder in Applications. If they are moved Software Update can't find them to determine if any updates are available. I don't know if that would work with the apps purchased from the Mac App Store. As a general rule, it's not a good idea to move applications from their installed locations. Those that do allow drag & drop installation into any folder are the exception.
A better way to organize your apps would be to create a folder some where, put aliases for the apps in there & then drag that folder to the Dock. I have a folder in my Dock of folders with aliases to applications organized by general function. I actually started with this back with OS 9 & the tabbed folders that could be collapsed at the bottom of the monitor.