Importing 3D objects from Photoshop to Dimension

Please help! I created a 3D object in Photoshop by first creating three 3D objects, and merged the 3 objects into 1. Then I exported this 3D object. When I import the 3D object into Dimension, it imports it as 1 object, instead of creating a folder with 3 objects inside so that I can manipulate each one individually.