outlook.com calendar – Outlook Web App: schedule meeting and expand a distribution list

Okay, this is crazy. I am trying to schedule a meeting on the Calendar page of the Outlook Web App. That part is fine. I use the scheduling assistant to choose a meeting time. That part is also fine.

However, I have all my attendees in a mailing list, and the scheduling assistant doesn’t know to look up their schedules. So it shows mine and anyone else I add manually, but won’t show the 8 people from the mailing list.

There must be a way — somewhere — to expand the mailing list out to the individual attendees so I can see their schedules in the scheduling assistant, and thus choose an appropriate meeting time. 15 minutes of web searching hasn’t found an answer.