All that these users need to do is to append the parameter standalone=1 to the website where Google Chrome can be downloaded. Here are the two download links for the latest official and latest beta version of the Google browser:
Latest official: http://www.google.com/chrome/eula.html?standalone=1
Latest beta: http://www.google.com/chrome/eula.html?extra=betachannel&standalone=1
Latest Test: http://www.google.com/chrome/eula.html?extra=devchannel&standalone=1
They warn that this version may not auto-update, but that may be exactly what you want in your environment if you would like to deliver versions in a controlled manner.
Unfortunately, when I tried this I kept on downloading the same version (172.28) as Prod only. According to Google Chrome Release Blog, QA is in v3 and Dev channel is in v4 right now.
I searched thru Google Chrome Forums and found a link to download full executable for every single release: http://www.filehippo.com/download_google_chrome/
and yet another one here: