Yes. Many of our users setup a hybrid solution and use both Exchange and Email in the same domain. Setting up a hybrid solution is great for reducing costs when not all the users need the full feature set of Exchange and collaboration.
The following is a use case for a hybrid Exchange / Mail setup:
Company executives need mobile access, calendar sharing and collaboration. All the other employees require email, but will not be accessing mail outside the office and don't need the collaboration features of Exchange. In this case the executives can be setup with Exchange accounts and all rest of the employees would be setup with Mail.
When setting up the account, just let us know that this will be a split/hybrid domain how many exchange and POP/IMAP mailboxes you need within the same domain.