Replacing sink drains

I am grateful for your advice, so thanks for providing this awesome forum!

I have an older Kohler double basin, cast iron sink I'd like to put in my kitchen. Caveat is that one drain is designed for a disposer. Is it possible to replace the stainless steel drain unit with a standard drain like the one on the other side, or should I just get a different sink?

The drain holes on the sink are the same standard size.

But is it possible for me to remove the one already installed in the sink that is for a disposer and replace it with one that is standard? That looks tricky and I'm unsure if I can get it off or not. Not obvious how to remove it. Thanks for any tips if it's possible!

http://www.easy2diy.com/cm/easy/diy_ht_3d_index.asp?page_id=35743512

If this link works go to section #4 that might show you what you need to know

Thanks Shacko! I figured it out with some fiddling. Turns out mine had a metal ring holding it all together that I was able to remove with a pair of needle nose plyers. Your link worked and was just what might have helped me had I not figured it out earlier.