We have a office 365 hybrid set-up with an Ex 2010 SP3 environment. All traffic is routed through the on-premise exchange.
One user, whose mailbox is hosted on 365, wants to mail ~300 people at once. Their 365 mailbox is configured to allow 500 recipients however when the user sends to 300 recipients, he receives a bounce back from the on premise server stating that the limit is set to 30. This is true as our default is set to 30 in the transport settings of the exchange server, however we don't want this to be increased across the board.
Is there any way we can allow this one user to be send to 300 recipients through our exchange server without increasing the default for all users?