I remember seeing this feature before. I was able to limit my employees to see only the last 4 of the social security number on their collection max screens. Not sure where to find it.
In Collections MAX Professional under the zip code there is an icon bar.
You need to click on the icon that looks like a gear and then enter an Administrator password.
Check off the box that says hash social security number so only last 4 digits show and then click OK.
You need to do this for each computer you want to restrict the SS# from showing.