Transferring a group email list to MacbookAir from Windows

[matNZ]

Hello, I have been driven demented by my Mac mail. II am a list manager for a community email list. I want to transfer a group email list (includes about 300 email addresses) to my Mac mail box. I do not want to have to do this manually. I have had to resort to copying the email list into an excel document then coping to a bcc line in an email. It does not always work and doesn't solve the problem long term. How can I transfer the list intact and have it come up in my Address Book as a group email list?

Any suggestions? Thanks.