Conference Exit Key to previous menu

Hello,

Here is the steps in my design,

  1. calls come in, announcement is played
  2. call is sent to IVR
  3. There are 5 Conference rooms
  4. user select the conference room number 1 to 5 and it is forwarded to the room
  5. in conference when they select “#” they must exit conference room and go back to IVR

The main issue is step “5”, I don’t know how to do it in freepbx.

Asterisk WIKI says:

https://wiki.asterisk.org/wiki/display/AST/Asterisk+11+Application_MeetMe

p - Allow user to exit the conference by pressing #
(default) or any of the defined keys. Dial plan execution will continue
at the next priority following MeetMe. The key used is set to channel
variable MEETME_EXIT_KEY.
keys

X - Allow user to exit the conference by entering a valid single digit extension MEETME_EXIT_CONTEXT or the current context if that variable is not defined.

I have no idea how to deploy the step 5 in FreePBX.