At least on Linux groovy GroovyConsole is a Script has the Following command:
startGroovy groovy.ui.Console "$@"
startGroovy itself is a script which starts Java. Within the startGroovy script you should be able to modify your classpath and add the missing librarys.
From startGroovy:
startGroovy ( ) {
CLASS=$1
shift
# Start the Profiler or the JVM
if $useprofiler ; then
runProfiler
else
exec "$JAVACMD" $JAVA_OPTS \
-classpath "$STARTER_CLASSPATH" \
-Dscript.name="$SCRIPT_PATH" \
-Dprogram.name="$PROGNAME" \
-Dgroovy.starter.conf="$GROOVY_CONF" \
-Dgroovy.home="$GROOVY_HOME" \
-Dtools.jar="$TOOLS_JAR" \
$STARTER_MAIN_CLASS \
--main $CLASS \
--conf "$GROOVY_CONF" \
--classpath "$CP" \
"$@"
fi