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Hi,
If I've understood you correctly then yes, you can achieve all of that with xoops.
The XOOPS core handles user registration, user groups and many other site-wide features.
To the core you will need to add modules to add functionality and many modules have their own additional permission-based features.
I think that if it were me who was starting a new site using XOOPS I'd start with v2.3.0RC although the official stable version is 2.0.18.1
As for modules, there are a number a "blog" type of module, inc weblog and lifetype. I'd try the latter first as, IIRC, it's been coded with 2.3.0 in mind.
For news there is the ubiquitous "News" module.
You will also want to install the Protector module.
I'm sure that others will give you advice too
Welcome to xoops!