retrieving bcc recipients of emails I’ve sent AND putting said recipients into a category in my outlook hotmail

I'd like to add (cut/paste?) a group of about 80 recipients of an email I sent to a 'catagory' that I've created so I can easily send mass emails to the same group (in bcc), but can't figure out how.  Can anyone help??  I've done both of these things before, but can't remember how (plus, it was before the conversion from Hotmail to Outlook, so maybe it's changed??)  Thank you!