Hello sir, i know i am new to this platform but i can assure u that i can provide u with the best services u need.
I read your project description, i have past experience with python Twilio API, that is used to make and receive calls, send and receive messages. As you described you want your program to detect PBX numbers and answer with its respective digits, this can be achieved in twilio with its lates release we have a sendDigits function that can be used to send digits.
It would be better if we could elaborately discuss your requirements, i am always open for any discussion just leave me a message.
Thank You
Regards,
Reshab