You have a variety of options here, I hope they help...
Firstly, I assume you are trying to write to a number of people within a particular group!!! In which case, set a personal distribution list with these persons in it.
Alternatively, create a rule which checks for messages AFTER sending and forwards them onto the other persons.
You cannot simply e-mail the address everyone@domain.com but you can create a group called this. If that helps.
FATZ