If the CMS could handle DID, you could do it.
The analog tenors could have one PBXTG on each PBX port, asociated with a diferent phone number.
The analog tenor part is the easy one.
I am not sure if the CMS could get a DID from the E1,and send those numbers forward to the VOIP side.
It will child play on a Cisco, using dial peers.
Best regards.