Demystifying Hybrid Free/Busy: what are the moving parts?

Hi Manju,

I deal much more with reactive support (break/fix ) than planning / consulting so you might need to check with an MS Customer Engineer/ Consultant /Partner for deployment advices.

In short, this is what I think of :

- Set bidirectional Organization Relationships between the two on-premises organizations (DAuth)

- Possibly Multi-hybrid setup with same tenant: https://docs.microsoft.com/en-us/exchange/hybrid-deployment/hybrid-with-multiple-forests#multi-forest-hybrid-deployment-scenario 

- Configure Hybrid Mesh using Organization Relationships (DAuth): https://techcommunity.microsoft.com/t5/exchange-team-blog/the-hybrid-mesh/ba-p/605910 

In the future, Engineering team might introduce Hybrid Mesh with IntraOrganization Connectors (OAuth) and would simplify things in terms of free/busy between hybrid organizations.