Question about handling missed calls only (RingCentral + Twilio + AI)

I’m providing an AI receptionist (Twilio number connected to Retell) for a client who uses RingCentral as their main phone system.

Client requirements:

Customers must call the business’s RingCentral number (not my Twilio number)
AI should only handle missed calls
“Missed calls” include: No one answers after a set number of rings ; The line is busy
In those cases, the call should be forwarded to the AI (Twilio number)
After a missed call, the AI should: Call back or text the lead

Problem I’m running into:

RingCentral seems to want to forward all calls, but I only want calls to hit Twilio if:

What I’m trying to figure out:

Best way to detect a “missed call” or busy line in RingCentral and trigger Twilio
Whether this should be handled via:
RingCentral call handling rules (ring count / busy forwarding)
RingCentral → webhook → Twilio
Or a middleware tool (Make / Zapier / n8n)
Any proven setups others are using where AI acts as a fallback, not a replacement

If anyone has implemented RingCentral → AI only on missed calls / busy, I’d really appreciate the guidance.

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