Smooth Group Import

From ZBrush Info

This plugin is designed for those who like to work with smoothing groups in Max or an app that supports them. It will import an OBJ into ZBrush and automatically crease the borders of any smoothing groups. If there are regular groups these are unaffected.

After installation you should have an Import & Crease button in the Tool palette (below the Import button).

Press the button and select an OBJ file from disk. You will have the option of importing into a mesh in Edit mode if you wish. The file will be imported and if there are smoothing groups defined the borders of each group will be creased.

To uncrease the smoothing groups after subdividing to the required level, SHIFT+click the Tool:Geometry:UnCrease button.

Download the Smooth Group Import plugin from the Download Center

For plugin installation instructions see here.