Repetitive Emails

This is a simple request for all my friends and relatives to review their group contact lists to help avoid sending duplicate emails. Here's what I really mean:

A receives an email from B. B has also included addressees C thru Z. A also has a distribution list for C thru Z and forwards B's email on to these same people. The result is an email, most usually a joke, getting sent umpty-ump times to the same people....and so on.

So just a word to the wise: please check (if it's not a blind cc) to ensure you're not contributing to email spam. Thank U!