Not a straightforward way. You could disconnect all connected viewers
by doing something like this, but it's admittedly a hack:
NOTE: {n} is the TurboVNC session's display number.
# /opt/TurboVNC/bin/tvncconfig -display :{n} -set Disconnect=1
# Xvfb :42 &
# DISPLAY=:42 /opt/TurboVNC/bin/vncviewer -password
`/opt/TurboVNC/bin/vncpasswd -o -display :{n} 2>&1 | cut -f2 -d:`
-noshared :{n}
(Press Ctrl-C to stop the TurboVNC Viewer process.)
# pkill Xvfb
# /opt/TurboVNC/bin/tvncconfig -display :{n} -set Disconnect=0
It is feasible to implement a feature that would allow you to list and
dump specific viewers, but it would be a significant effort. (I'm
always willing to implement features like that if someone pays for my
labor, though.)
DRC