MS Exchange 2010 Deployment

I need some advices on Microsoft Exchange 2010 server deployment for a small business with 25 users that operate mainly through emails. My questions are:

1. Can i use only one physical server running Windows Server 2008 Standard for all of Exchange 2010 server roles?
2. I would like to know if Exchange 2010 transport rule be set up where the incoming emails be distributed to specific 2 email accounts in an alternate fashion (i.e. first email goes to account A, then the second email goes to account B, then the third email goes to account A, then the forth email goes to account B, and the pattern repeats as described).