Hi @ Atul Tyagi,
You can refer to the following command to get all user mailboxes in a specified domain:
$users= Get-Mailbox -resultsize unlimited -RecipientTypeDetails UserMailbox | Select-Object displayname -expandproperty emailaddresses| Where-Object {$_.smtpaddress -like "*contoso.com*"}
Then refer to this command to add all users to the requestinpolicy for this resource mailbox:
Set-CalendarProcessing -identity “******@contoso.com” -AllRequestInPolicy $False -RequestInPolicy $users.smtpaddress
Please use the following command to verify success:
get-CalendarProcessing -identity "******@contoso.com" |fl
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