We have a small team who wish to use Office 365 for collaboration with partners. They only really want to use SharePoint; they're happy with their internally hosted Exchange for email, and are not looking at online Exchange. Only a handful of users in the organisation will use this online SharePoint system.
However, when we create new users in the Office 365 trial their email addresses are of the form email@example.com. We would like them to be of the form firstname.lastname@example.org, so that if the partners try to email the users they'll have the right address.
Is this possible? We already have a domain ('example.com' in this example), but it's being used to host the company website, and we don't want to affect that.
I've read about Office 365 and Single Sign-On, but that requires ADFS (which we don't have, and expect would take too long to implement), and our team is actually happy with having to log-in to Office 365 - but they just want their email addresses to be correct.
How might we achieve this? Most of what I've read seems to be about using Exchange Online, or Signal Sign-On, and I'm a bit bewildered. Is it just a matter of adding a domain to the Office 365 plan, and then not using it?