Probably a basic Address book/Mail question- group email list

Is there away to take all the email address in an email that was sent to me and create my own email group list on my computer?

i.e. Joe Smith sent me an email along with 25 other people from Rotary, I need to set up this same group of people as my own Rotary email group.

I'm having a hard time trying to find an easy way to do this....the long way seems to be add each email one at a time to the address book.

Thanks,
Todd