Paradigm shifting via changing desktops in KDE4 ?

[Linuxguy123]

In KDE3.5, we used to be able to set an option such that applications
didn't appear on multiple desktops or on the task bar of another
window.  

Ie:  I could have my email and general apps open (and displayed on the
taskbar) on desktop #1 and my programming apps on the taskbar and
desktop of desktop #2, word processing on desktop #3, etc.   I could
then switch between paradigms by simply changing desktops.

How do I do this in KDE 4.2.x ?  

I can set which desktop an application belongs to without too much
trouble, but the task manager shows all the applications that are
running on all the desktops, not just the desktop that I am currently
working in.  How do I limit the task manager to show just the
applications that are running on the current desktop ?

As you can probably surmise, I have not investigated the multiple
desktop views part of KDE4.

Thanks
LG