SharePoint Extranet - Add Users

[David Gorman]

Hi all,

We want to allow a external organisation that has a Office 365 tenant access to a SharePoint site we have. The tenant is fairly small, around a dozen people.

We can of course just share the site with the each individual user. Can we set it up so any user from that Office 365 tenant can access the site? That they don't need to be invited by us? Is there someway to specify that any user from @  contoso can access the site? 

[#2]

Yes, you need to ask your O365 admin to configure an inter-tenant collaboration.

Reference: https://docs.microsoft.com/en-us/office365/enterprise/office-365-inter-tenant-collaboration

[#3]

To my knowledge this is not possible. You have to invite individual users to collaborate. You can restrict domains etc. but not allow anyone from a certain domain to access your resources.