asterisk users - May 2013 - changing ringtones to a group of phones

Hi all,

I've been modifying the ringtone on a group of Snom phones like this, 
depending on certain dial-plan conditions:

Exten => s,1,SIPAddHeader("Alert-Info: 
<http://192.168.0.200/tel_ring01.wav>")
exten => 
s,n,Dial(SIP/mjc_office&SIP/mjc_home&SIP/mjc_lab&SIP/mjc_server,20,trj)

Now, I'm migrating slowly to Digium D70 phones, which have a different 
Alert-Info syntax (and different ringtone names).

How can I dial a group of phones simultaneously, say half Snom and half 
Digium, with different sip alert-info headers?

- Mike

Maybe using a LOCAL channel could help. One ext. for Snom with Snom 
header, another for Digium with Digium header, then simultaneously call 
both local channels, which then call the appropriate phones.

jg