Local Survivability with Operator Connect

Wanted to see if anyone out there has  stood up a form of Local Survivability for PSTN access in the event someone loses connectivity back to the Teams tenant or an M365 outage?

Not sure if it's on the roadmap to have SBA's work in parallel with OC clients? I'd hope you could have the IP Phone register to both OC and the SBA and in the event OC was unreachable the phone would use the SBA to dial out to the PSTN.

I understand we can standup different ISP's for carrier diversity but if both went down to a fiber cut, this client needs access to 911 as they are a city with many recreational facilities for the residents that use them.

Any thoughts on how we can roll out a Local Survivability option with Operator Connect would be appreciated .

Thanks!