Setup "trust" between multiple tenants in group

[SpamMeNot]

Hello everybody

We have several tenants in our group, each company has its own, including the holding company.

Some of the senior managers work for two or more companies at the same time. 

Currently, these employees have one user in each company/domain/tenant and a poor user experience due to changing logins between companies. 

Is it possible to set up a trust like between two domains? The employees should only manage one login.

Thanks in advance

[#2]

Not really, best is to merge them all in a single tenant. Other than that, you can play with the B2B/Guest users experience, but it has some limitations.