The answer is no. This is because the second scanner is not in trunking mode when Etrunker is driving it so it (780xlt) will just show the frequency it's on, and Etrunker doesn't send alpha tag information to your second scanner.
Well, what I was thinking would be nice is a mobile set-up where the first scanner and the computer would be mounted somewhere out of the way and the monitor scanner would be mounted in a convenient location that could be watched.
Trying to figure out a way to mount two scanners and a computer in the front of a car is not the easiest thing to do.