yes/no parameters

[RafeRedmond]

How can I make a yes/no parameter so that when it is on, another yes/no parameter turns off? I was thinking of using a conditional statement (such as if...), but I cannot make it work. Please help if you have done this before or have any ideas.
Thanks.

[aaronrumple]

For parameters ParamA and ParamB:

ParamB = not(ParamA)

[Chirag Mistry]

Here's a quick tip on this by Steve
http://revitoped.blogspot.com/2005/11/make-up-my-mind.html