In accordance to Inouye (2011), the directives of Uniform Deceptive Trade Practices Act clearly state the rights of the customer in case of "untrue or misleading advertising" (p.461). In this case the resort advertised about “a peaceful, scenic ride” which, incidentally, was not at all peaceful. Even thought it can be argued that the trail hands, Tex and Rex, played a practical joke and the resort has no direct involvement in this act, it is obvious that the trail hands, Tex and Rex, are employees of the resort and the resort should be held responsible. Thus, even though Tex and Rex were primarily responsible for the injury the resort is in no position to deny its accountability about your well being and thus the resort is liable to pay damages.
The resort, on the other hand, cannot seek reimbursement from Tex and Rex as they are just employees and they can only be fired or suspended and not held liable for reimbursement unless there are clear scope of such reimbursement in their job contract. However, if Tex comes to you and says that the whole scheme was Rex's idea it will be unwise to agree with him in exchange for securing his testimony against Rex because in that case the liability of reimbursement is removed from the resort and become engaged with Rex, who is clearly not in the best position for the reimbursement, at least not as eligible as the resort. However, on a legal note, Rex can be held responsible based on the testimony.
Nevertheless, it is important to obtain primary evidence that the two trail hands, Tex and Rex, are indeed employees of the resort and obtain another medical certificate that the mare, Molly, is primarily a difficult horse to ride, particularly for inexperience riders. These are the main information needed to sue the resort and the two trail hand.