asterisk users - Sep 2013 - confbridge - play different sounds to caller and bridge at same time?

When a caller enters the confbridge, I want to play a sound file
('ring')
for the caller and a different sound file ('type of caller') to the
bridge
(all participants or just the admin?) at the same time.

It's OK if the bridge hears the 'ring,' but the caller should not
hear the
'type of caller.'

Any clues?

-- 
Thanks in advance,
-------------------------------------------------------------------------
Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                              Fax: +1-760-731-3000