I seem to recall others doing that, but you will need to see if it voids your warranty or such (which is likely). I also would get it in writing if your salesman says it doesn't.
There are topics on here discussing the pros and cons of putting a hitch on your trailer.........as well as the frame mods needed for it. Towing two trailers at the same time is definitely different.
Good luck and congratulations on your new Fiver.
2011 Flagstaff 831 RLBSS
I used to be addicted to time travel, but that's all in the past now.