Office 365 single tenant multiple domain multiple sharepoint

Question

I have two tenancies lets call them ten1.com and ten2.com. Each one has their own SharePoint ten1.sharepoint.com and ten2.sharepoint.com. ten1 is being migrated into ten2.

The users and domain name are being kept as they were in ten1. The company has merged but is still separate. ten1 migrated users will still use ten1 as their domain for email/skype etc. It's my understanding that if I migrate SharePoint from ten1 it would then become ten2.sharepoint.com/ten1. I need to keep the SharePoint separate so in ten2 I would have ten1.sharepoint.com and also ten2.sharepoint.com.

Is this possible and how could I go about it?

Answer 1

One sentence in advance: If you ask google about this topic, you get a lot of information about a feature named "Public Site". This feature is no longer available, so all that information is invalid for today's deployments.

If you enable SharePoint on your O365 tenant, you will be assigned a URL tenant.sharepoint.com. This cannot be change or extended right now. So think well about your tenant name!

If you want to migrate your existing SiteCollection from ten1 you need to create a SiteCollection as you already mentioned (ten2.sharepoint.com/tensite1). I would recommend you to use an ISV-Tool to perform migration (ShareGate, Metalogix). "Save as Template" can also work, but with lots of limitations (e.g. doesn't work with publishing-features enabled).