So it looks like Twitter is going to be handling this using "Lists" .
TWEET: RT @andybeal Be Warned, Twitter Lists Will End in Tears!http://bit.ly/edRfS
and see Twitters blog entry here:
http://blog.twitter.com/2009/09/soon-to-launch-lists.html

I really like how tweetdeck groups sync between the iPhone client and the desktop client. I dont mean to rant here however there seems to be a major missing element to current microblogging technologies, specifically twitter and friendfeed. I wish that these same groups could be synced across all twitter applications and services like ubertwitter, friendfeed, peoplebrowsr, tweetgrid, etc...
Does anyone know when Twitter may have this functionality and if it is even planned?