I have a dialplan with 3 extensions.

100, 101 and 102

100 and 101 are SIP phones

102 plays a wav file

From 100, I want to dial a number which causes the following:

drops 100 into a meetme room
Originates a call from meetme room to 101 (101 is on auto-answer)
Then originates a call from the meetme room to 102
We both (100 and 101) listen to the wav file (102)
and then everything gets hung up.