[Asterisk-Users] SNOM Shared line DevState

[asterisk]

Hello,

Does anyone have some ideas on how to setup a shared line on several 
SNOM phones in a reliable manner?
For the following scenario:

Calls enter on number 123. They do not have to ring anywhere (although 
this could be the case), I just want the LEDs on a series of SNOM light up.
Phones x,y and z have 123 subcribed as "destination 123" under a 
function key.

Question: where do I send the call initially?
When I send it to a real SIP phone (registered as 123), it works.
 I've tried sending it to a Dial(Local/321) and have calls wait there on 
ringback. But I cannot do a pickup() since the state is RING and not 
RINGING. Nor DPickup() or PickupChan() work on chan Local.
In order to have a real SIP channel, I had asterisk register a SIP user 
on itself. But asterisk detects this and converts it to a Local/xyz 
automatically (why so intelligent?)
I also need to have any number of calls being 'parked' this way, so a 
real phone does not seem like the best way to go about this.

I've toyed around with DevState but some how I can't seem to get this to 
work in all cases, especially trapping all hang-ups and setting the 
state back to 0, is a problem. Is there a way to ALWAYS jump to a 
context/priority to do cleanup actions?

any ideas are welcome,

Regards,

Steef