Caching server for local use of an Exchange Online setup
We're about to migrate our existing on-prem Exchange 2003 server to the cloud using Microsoft's Exchange Online.
Before we make the final decision and begin the process of migration, I have a few concerns about bandwidth use and storage.
One of the offices that currently use our on-prem server (in fact, it's the office that the server is physically located) has around 40 users on the local network. One advantage of the on-prem setup is that any internal emails go directly to the server on the LAN and are routed to the various mailboxes... all of this without the email going www.
My question is basically, is there a way to have a Exchange Online "replication or cache" server on-prem so internal emails can continue to do what I've mentioned above? ie. If a user sends an email to all staff with a 25MB attachment and rather than it being DL'd from the Exchange Online cloud 40 times, it is just accessed on the LAN.