How to use join in bayonne2?

In bayonne1, there is an example of joining:

#script 1
answer
sleep 10
^1
start.group group=default script="script2"
^2
wait id=322 maxTime=1000

#script 2
sleep 3
send %session.parent message="hello"
join id=322
exit

But it seem there no "start.group" and "%session.parent" in bayonne2, Is
there any

example for bayonne2?