Yes, there are different ways to restrict content access, but it depends on what kind of restrictions you want to place and on whom you wish to place those restrictions.

Node Restriction

The most straightforward way of restricting content access to your audience is to unpublish a node.

Making private content for your group members is very simple. This allows content access to users who are a member of your Organic Group - other site users and your external audience will be blocked.

Block Restriction

All blocks can have different visibility restrictions set on them.