Import the model first. Set the family color by click on the "color icon" under the "A" for the object properties. Select a color that you can remember (don't used the solid blue -- it's the camera and grouping the camera with your model will be a problem.). Click on the "A" and give it a object name. Now, un-group your model. Use the TAB key to cycle through the different meshes and set the desired materials. When finished, select either your object name or the family color and re-group the model. If you want, add the model to the object library. You can work several models this way and then add them to your scene later.