If a client has multiple extensions and you want all the extensions to ring upon an incoming call, follow the following steps.
Setting up main Extension
The main/first extension has to have the number allocated.
Setting up Extensions
All the extensions thereafter gets the number assigned to it by setting it in 'Currently using CallerID numbers'
Change and assign the number to the extension.
Ensure the number is set as default.
Setting up Extension group
In the main client screen, create an extension group
Name the group, eg: 10
Add all relevant extension in the group
Setting up Cascading
In the main client screen, add an 'incoming call rule'
'when CallerID' = is any
Ring below for 60 seconds
Call number 10 after 3 seconds
This will call extension group 10 after 3 seconds.
This facility will allow receptionist with opportunity to pickup before going through all SIP accounts.