Bought wrong computer - need help finding drive cage

Hi all. I bought a HP ProDesk 600 G4 MicroTower. I meant to purchase the SFF.

The MicroTower drove cage only holds a single 2.5” and a single 3.5” drive, not counting the 5.25” drive bay. It is welded together in a manner that does not allow it to be modified to hold the additional 3.5” drive.

The Drive cage on other similar ProDesk models can hold two 3.5” inch drives. Does anyone have a lead on the part numbers for ProDesk drive cages? I have been unable to find them with my google-Fu.