Preview after login

Hi,

how can I achieve a preview mode to testers of a website which is not yet online for public?

Do I have to put all documents to a document group "preview" and assign webusers to this group and put the modx config mode to "site online"?

This would be very uncomfortable, as I had to edit every document - I didn’t find a possibility to assign all documents to a document group in one go, like with the doc manager.

How do you achieve preview modes of websites still being built?

Cheers,
Frisco