Category/Post Visibility ?

Hi there.

I’m creating a work in progress blog for a client of mine.

However, they have 2 seperate groups, two has to see different “progress”es.

I thought, creating 2 seperate categories for 2 seperate progresses can be good.

But the problem is, I do not wish everyone to see the posts. I want to create users and give them the ability to see different categories. is this possible ?

Thanks.