Adequate Dual Hitch Extension

Thank you for the information. My diesel has a 10,000# hitch rating and I will have to find out what the tow rating is. I'm currently have no drop or rise in my Blue Ox and towing. I believe the 2 ideal options that you have been suggested would be a "straight thru" adapter, or a bicycle carrier that you have suggested that slides over the 2" extension that slides into the receiver. I'm still googling to find more about either of these 2 options. If you happen to run across a bike carrier that does slip over, please let me know who manufactures it. Thanks again