List users with the ability to send to an Exchange Online Distribution Group
Exchange has the ability to limit sending permissions on Distribution Groups. Finding which Distribution Groups have user sending permissions assigned to them can be very time consuming using the portal.
To make it quicker, you can list the accounts that have the ability to send to a specific distribution group using PowerShell.
$FormatEnumerationLimit=-1 # This allows the property to be expanded in format-table Connect-ExchangeOnline Get-DistributionGroup -Identity XXX | Format-table -Wrap -AutoSize -property name,acceptmessagesonlyfrom # Change XXX to the Distribution Group SAM account name