As far as I am aware Fences doesn't do that, but I know ObjectDock Plus does (I have both).
With objectdock plus you can have tabbed bars, and therefore switch between the tabs depending on which icons you want access to, for example my primary tabbed dock (ive got it on my main screen at the top) has the tabs 'System', 'Games', 'Internet', 'CS4 & Vs 08' and 'other'. These contain all my activity specific icons (eg, System contains Computer, command prompt, control panel, AVG etc.) so that I have all my relevant icons handy.
I have a speerate dock for my Start Menu, Recycle bin and clock (my version of the startbar, with tasks and system tray on right and left of screen respectively). I come to use fences on my second screen which has a fence showing all my internet browsers and some specific file locations and another fence with all my random crap.
Whilst I do appreciate the possible benefits of being able to have cyclable fences I doubt it is in Stardocks interest to take away from ObjectDocks function, although I would have to point out I do prefer my combination setup both aesthetically and functionally (mainly the re allocation of taskbar functions and the ability to always have access to my apps by throwing my mouse to the top of the screen, and not having to flip to the desktop.
Anyway, that was a bit long winded and a bit astray from topic, yet I hope I answered your question if only with a demand for $19.99
