Two years later, a quick FYI and SEO boost for the question since it took me a few minutes to locate this info (I wasn’t a community member here yet).
I did this today and it’s still exactly this simple for two related entities to dial out with different numbers and CID using the same PBX and same trunk. Two minor things to add to the above by omnicom:
- Be sure to disable circuit caller-id at the carrier (easy w most VOIP providers) and set sendrpid=yes in your existing trunk settings.
- When adding a new outbound route to an existing system, don’t forget to check the existing route and extension CID/DID info. If you didn’t have DID/CID info there it the first place (ie: was handled by the trunk provider), calls might not terminate or have bad CID data on the original route.
- Don’t make any typos. Failure to exactly matching the expected DID/CID info will probably not be handled well by your trunk provider.
Of course, the assumed usage scenario is the same tenant running multiple companies. Anything beyond this, I would at least add a separate trunk, if not another PBX outright.