Unfortunately, no. You cannot set a custom status for each of your friends. But, you can silence notifications for one person. Here's how: 1. Click the dropdown arrow to the right of your friend's screen name in the Steam chatbox. 2. Click Notifications. 3. Uncheck the box next to Use my default notification settings. 4. Uncheck the boxes next to When I receive a direct chat message. 5. Click Confirm. Although the user can see you're online (or whatever your default status is), you won't receive any notifications if they try to communicate with you.