Looking for a backup solution for a large enterprise Exchange server

Hello, I'm looking for a backup solution for an Exchange server 2010 with over 500 mailboxes. We are a multinational company, and our exchange server mail servers are based in London. I'm looking for a solution that would allow me to backup individual emails on the exchange servers. Currently we backup at block level, meaning we have to restore the entire Exchange databases before we can recover the data. This isn't acceptable, so we need to get something in place that allows us to restore individual emails. Any suggestions? Thanks