This is a frequent topic of discussion, particularly on the open roads forum. If you check trailer towing laws, Florida is one of a number of states that do not allow "triple towing". Triple towing in the RV world means a tow vehicle and two towed vehicles.
Although some states do not allow it, I am not sure I have ever read where someone was actually stopped for doing it in one of those states. However, if you did get stopped, you would probably have to drop the second trailer, take the first trailer somewhere and leave it, and return for the second one.
Here is one towing law site. Can't guarantee the accuracy of the info.