I have two exchange servers in different companies and also in different AD forests. One of them is setup in hybrid mode for Office 365 with a few hundred senior people already on Office 365. I need to bring some users in the other exchange also to the same Office 365 so they can collaborate. How can I easily do this as they still need to retain access to everything they have access to now in their current forest.
The crude method would be provide an account in the domain that Office 365 runs in, this would be quick but also a pain both for the user and for admin. Hopefully someone has done this already. I'm dealing with a large volume of users so any migration would require considerable effort and resources, thanks.