Is it legal to criticize another's advertisement in our own advertisement?

What is the legality of one non-profit criticizing another non-profits in an internet video? I want to run an ad which shows a snipit of another non-profit org's ad, state how much money this ad has rasied for them, state their fundraising appeal (what they are saying to money goes to) is lifted from yet another non-profit and while it accurately reflects the work of the originating organization it does not accurately reflect the work of the organizatin being critized. The adverftisement will then advocate visiting a web site where they can find the name of an organizatin which does do what they think they are spending their money to do and also can print a form the cancel their membership in the organizatin being criticized. Can I show a snipit? What are the other issues? - Is this your question? Add additional information