password protect different posts for different groups

I want to make a wordpress site for a friend who is a photographer and he wants to post his client’s photos for them to see, but each client needs their photo gallery to be private just for themselves and there families etc. So, I was wondering if it is possible to make different groups of users that only have access to a specific post to view the respective photo galleries. In other words, the Smith family members sign up and they nominate/categorise themselves as belonging to the ‘Smith’ group, and then when they sign in they only have access to the Smith family post. What plugins would I need for this? Thanks heaps.