BulkChangeO365GroupSMTP

#Simple script to change all Unified Groups (Office 365 Groups) Primaty SMTP email address to a new domain.
#It's recomended to have a diferent email domain for Office 365 Groups, so they dont conflict with regular user and system mailboxes.

$groups = get-unifiedgroup | select-object name,alias

Foreach ($group in $groups) {
  Set-UnifiedGroup –Identity "$($group.name)" –PrimarySmtpAddress "$($group.alias)@groups.contoso.com" 
}

One that I use often during hybrid migrations to Office 365, so leaving it here for others to use :)

In order to set a default email policy for Office 365 group creation, the following command can be used:

New-EmailAddressPolicy -Name Groups -IncludeUnifiedGroupRecipients -EnabledEmailAddressTemplates "SMTP:@groups.contoso.com" -Priority 1