Well, I can't do that under the "Virtual servers" but looks like a may be able to do it here... under "Special Applications". It allows me to enter a range. Is this what I need to use? How exactly do I enter the info for "Trigger Port" & "Public Port"?
Special Application
Special Application is used to run applications that require multiple connections.
Enabled Disabled
Name
Trigger Port -
Trigger Type TCP UDP Both
Public Port
Public Type
TCP UDP Both