Hi @Buczek Piotr .
Thanks for reaching out to Microsoft Q&A
As of Today, the only option available to help in your scenario would be to use B2B users. However, there is a better approach of using it which is the Cross-Tenant Synchronization feature.
Cross-tenant synchronization automates creating, updating, and deleting Microsoft Entra B2B collaboration users across tenants in an organization.
Here are the primary goals of cross-tenant synchronization:
- Seamless collaboration for a multitenant organization
- Automate lifecycle management of B2B collaboration users in a multitenant organization
- Automatically remove B2B accounts when a user leaves the organization
You can find more information about this feature on this document: https://learn.microsoft.com/en-us/entra/identity/multi-tenant-organizations/cross-tenant-synchronization-overview
This might not be what you were expecting, but I hope it helps you.
Thanks,
Fabio