As the /etc/init.d/openvpn script (which is what gets executed by /usr/sbin/service) does not offer any options to do it (at least with ubuntu-10.04), the answer is no.
But since it is all scripts, you can just edit /etc/init.d/openvpn and add something like
named-restart)
log_action_begin_msg "Restarting $DESC $2"
PIDFILE="/var/run/openvpn.${2}.pid"
NAME=$2
log_daemon_msg " Stopping VPN '$NAME'"
stop_vpn
sleep 1
log_daemon_msg " Restarting VPN '$NAME'"
start_vpn
if test -z "$PIDFILE" ; then
log_warning_msg " VPN $2 is not running."
fi
;;
after the
case "$1" in
dirctive. Later, you can simply call service openvpn named-restart <vpn-name>.