adding third wan link to FortiGate

Hello,

We have purchased a Fortinet unit with the following specifications:

Fortinet - FortiGate 94D PoE

QuickStart Guide of this unit shows a diagram of the device. According to the diagram, the device has the following ports:

USB MGMT (USB Mini-B)

DMZ 1 & 2 (SFP)

WAN 1 & 2 (RJ-45)

LAN Ports 1-24

LAN PoE Ports 25-48

Currently, we have DSL Internet Connection 1 from Internet Service Provider 1 and DSL Internet Connection 2 from Internet Service Provider 2. We have connected connection 1 to WAN 1 and connection 2 to WAN 2. Our requirement is to add DSL Internet Connection 3 from Internet Service Provider 3 to the Fortinet/FortiGate unit. However, the unit only provides two WAN connections, WAN 1 and WAN 2. Is it possible that we could add the DSL Internet Connection 3 from Internet Service Provider 3 to the FortiGate unit?

Regards,

Shehzad