New-Mailbox -Name "MailBoxName" -Alias MailBoxAlias -Shared
Set-Mailbox MailBoxAlias -ProhibitSendReceiveQuota 5GB -ProhibitSendQuota 4.75GB -IssueWarningQuota 4.5GB
New-DistributionGroup -Name "Shared Mailbox Access - mailbox@domain.dom" -Alias "sharedaccess-shared-mailbox" -Type Security
Set-DistributionGroup -Identity "Shared Mailbox Access - mailbox@domain.dom" -HiddenFromAddressListsEnabled $True
Add-RecipientPermission "MailBoxName" -Trustee "Shared Mailbox Access - mailbox@domain.dom" -AccessRights SendAs