What do you mean by "access"? It would not show up, for example, if you click the To button in an email to get a contact list.
The strategy would be to keep the list in an Excel file, and have a macro in Outlook that opens the Excel file and reads the names to compose an email to that list. You would either run the macro from Outlook or set up a button to run the macro. Alternatively you could use an Excel macro to send the email. How much detail do you need?