I have problematic knees and have not been able to run since I was a teen - I simply can't do the high-impact stuff. I have been doing lower impact activities like hiking, swimming, cycling, skiing, etc. ever since. Are there any multisport events I can do that absolutely positively don't involve running?

Or, am I understanding right that there are tri-teams where each person does a different leg of the triathlon? What is a good way to get hooked up with this kind of thing?