Reliably? There are a few places:
- inbound calls from trunks can be configured to go to a user defined context, which in turn sends the call to from-trunk
- diaplan hooks, there are a handful of “hook” macros that are called immediately prior to dialing, such as
macro-dialout-trunk-predial-hook. You can safely define these macros in extensions_custom.conf. - Custom Destinations. If you want to create a call flow through a block of dialplan, you can define a custom destination, and close your dialplan with a
Returnto send the call back to the GUI destination.
and last resort:
- by redefining existing generated contexts in the override file.