PS C:\> Get-ChildItem -Recurse -File -Path D:\33\ | Group-Object -Property Directory,BaseName
Count Name Group
----- ---- -----
1 D:\33\11, bbb {bbb}
1 D:\33\11, ddd {ddd}
1 D:\33\22, bbb {bbb}
1 D:\33\22, ddd {ddd}
When the message is accepted and email is sent to the categorizer, the mailbox level RecipientLimits (if it is not set to unlimited) or Transport level MaxRecipientEnvelopeLimit are checked. If the number of recipients exceeds this limit, the message is rejected and a bounce message is sent with the error 550 5.5.3 RESOLVER.ADR.RecipLimit; too many recipients.