It looks like you will have to make a choice:
If you want to direct your inbound calls to matching extensions, that is the only reason to order DID lines.
If you want caller ID, you need standard PSTN lines with caller-ID service, but you will not have the automatic extension connection.
Or, you can get a PRI line and get the best of both worlds. Have you looked into getting a fractional PRI line?
You cannot get the DID functionality (extension connections) with standard PSTN lines, but if all you want is to attach a bunch of numbers to a few lines, maybe local carriers offer this service.
