Monitoring WAN Traffic

I have an Adtran provided by my ISP (telepacific) for our two bonned T1s. Off of that Adran, they hand us a single Ethernet cable that is plugged into an unmanaged switch which provided a link to our three devices with static IPs. Our Sonicwall, Our Webstream Computer, and Test webserver. We have noticed that our webstream on this bonded T1 is buffering the users end. Using a basic Solar Winds interface, we've been able to determine that there is a lot of inbound traffic that is maxing out our 3 Meg link. Question: If I install wireshark on the webstream computer will I be able to see all traffic coming in, or just that which is destined to the Static IP of the webstreamer? I assume I can point wireshark to the LAN interace that Telepacific gives us, right?