I've got some email addresses in *.xlsx file (about 300) and I want to import them into one distribution group in Microsoft Exchange.
The problem is some emails has already got a corresponding contact on my server (about a half of those emails) and other doesn't.
What's the easiest (or most elegant) way to add all those mails into distribution group? I don't want to check if 300 email addresses have their contact and then adding it all.