I need to create role groups

I have been asked to set up "email enabled role groups" that users will be placed in describing their roles, then those groups will be placed inside account groups for an entire department. For example, the legal department would have role groups legal_paralegal and legal_attorney and those groups would be placed in the larger group for the legal department. I have just been going to the Exchange server and creating them in the exchange console under distribution groups. That way they are already email enabled and easy to create. I was wondering though, is that best practices? Is there a proper microsoft procedure for setting up roles groups? I want to to do this properly and do not want to do anything that will cause me problems later. All advice appreciated...thanks