ExpandGroup doesn't work if members are hidden objects

I was attempting to use the EWS ExchangeService.ExpandGroup method with a group in Office 365 that has hidden members.  It works if the members are objects visible in the GAL however if the member is hidden from the GAL, it doesn't return it in the list.  Is there a way to see all group members like you can from powershell (i.e., using get-distributiongroupmember).  

I am trying to find a non-powershell way of managing groups in Office 365.  I guess I can look at the Office 365 Graph API but to be honest there's a bit of a steep learning curve to get start with it and the overhead of registering the app in the tenant.

Thoughts?