Load Balance Incoming Traffic ?

Dear All

Please I have the following scenario.

3 servers voip / mail / terminal one load balancing router 2 internet connections (static ip`s)

My concern is to load balance incoming traffic since the outgoing traffic is being taking care by the load balancing router.

For instance all offices connect to the mail server via the internet same for voip and terminal services. The mail and voip clients are set up with one of the static ip`s and the router forwards the request to the appropriate server.

But obviously like this there is no fail over nor load balancing cause all requests are being directed to one internet connection.

Anyone has a suggestion was thing of a dns server, does this make sens ? or maybe a hosted option ?

Thanks Justin