I'm afraid I don't know the answer to your question (ought to, but the old memory ain't so good!) but I thought I should wonder out loud whether having two versions of the same suite of apps isn't going to cause headaches with things like file associations, system files and registry data. Try it by all means, but make a restore point and be prepared for glitches. On the other hand it may just work fine!
Regarding your question, some (but by no means all) installers have an option for that during the install process. MS Office's install wizard may have it, but bear in mind that you might need to remove and re-install any such program if your access needs change. As for whether it can be adjusted at in time and for any program, I don't think so, but can't be 100% on that.
Hope that helps.