how to create custom group email id?

i want to create a custom email group for some people i know In the organization i am...we kind of have a service where we can create a group...!!! as in a group is 5cea....whenever u send an email to the 5cea@gmail.com all the 60 member of the group will receive the email..!!! i want to create the same kind of the group for the people i know outside of the organisation is there any service where i can create the group like that...??..it would be really great..!!