I have a new Office 365 for business setup with several Internet domains on it. When a create a group in Outlook, the default domain is automatically filled in with no way to change it. If I do it through the admin interface then I can select any of the domains.
The question can I grant my users the ability to create groups that are not in the default domain without needed to get an administrator involved.
This is a simple on-line only setup with no on-premises sync.
I am not sure there is any way to allow users to select which domain they should use themselves, however you should be able to select defaults for different groups of users using email address policies:
Scenario 1
The following example shows you how to provision all Office 365 groups in your organization in the groups.contoso.com domain.
Scenario 2
Let's say you want to control what sub-domains Office 365 groups are created in. You want:
Office 365 groups created by students (users which have Department set to Students) in the students.groups.contoso.com domain. Use this command:
Office 365 groups created by faculty members (users which have Department set to Faculty or email address contains faculty.contoso.com)) in the faculty.groups.contoso.com domain. Use this command:
All other users in the groups.contoso.com domain. Use this command: