Hi @Sean McMahon ,
Welcome to our forum!
As I know, we can create a shared mailbox which can be used to provide a common calendar, allowing multiple users to schedule and view vacation time or work shifts.
For more information about shared mailbox, please refer to: Shared mailboxes in Exchange Online.
Then, after creating a shared mailbox, you can refer to this article about how to open a shared mailbox: Open and use a shared mailbox in Outlook.
Hope the above help!
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