Migrating office365 users to new tenant

[anon1m0us]

Hi,

I need to get users who are in O365 E3 from an existing tenant to a new one. The issue is, when I am done migrating their mailboxes, how to I join them to the NEW domain automatically. I do not want them to do it or have people running around disjoining and rejoining. 

Is there an automated way, or tool that can disjoin a computer from an existing Azure domain and log them onto a new one?

[#2]

What exactly do you mean by "joining them to the new domain"? Azure AD join? Join to an on-premises domain? Something else altogether?

[#3]

These are 365 users, not onprem users.

If i migrate them from tenant to another, what happens when they log into their computer? Do they need to disconnect from the current organizations and added to the new one?

[#4]

Here is a detail explanation. I have 500 users on 365 using F1 & E3 licenses.

I need to separate each 100 to their own tenant.

1. However, 5 bosses need to keep their access across all tenants to be able to access the sharepoint sites for the documents.
2. I do not want users to need to rejoin their organization when they log in after the move. How do I automatically migrate the computers to the new organization.