There is call forwarding APIs in RingCentral which you can route the call:

https://developers.ringcentral.com/api-reference/Call-Forwarding/createForwardingNumber

You can predefine the call forwarding rules and apply it to incoming caller id.

You can configure with Online Account Portal at https://service.devTest.ringcentral.com

As per this link: https://www.ringcentral.com/office/features/call-forwarding/overview.html

Can calls be forwarded to non-RingCentral numbers?

• Yes. You can forward calls to any number and any device.