Connect-Exchangeonline


Set-UnifiedGroup -Identity "NAMEHERE" -HiddenFromAddressListsEnabled $true 

Set-UnifiedGroup -Identity "NAMEHERE " -HiddenFromExchangeClientsEnabled




Check met: 


Get-UnifiedGroup -ResultSize Unlimited | Select DisplayName, Alias, PrimarySmtpAddress, HiddenFromAddressListsEnabled 

Get-UnifiedGroup -ResultSize Unlimited | Select DisplayName, Alias, PrimarySmtpAddress, HiddenFromExchangeClientsEnabled 


https://petri.com/hiding-office-365-groups-exchange-clients