Trying to figure out the name of a movie

Trying to figure out the name of a mid to late 70s TV movie about three brothers who end up in the castle of a woman scientist with three daughters. Seems she always wanted to conduct an experiment with a male baby to prove that they could survive a fight with a tiger/lion, but couldn't because she only had girls, so she traps one of the brothers, strips him to his underwear, and dumps him into a pit with a tiger/lion. The other brothers and the daughter rescue him and then happily pair off. The brothers may have been real life brothers, but not the Hudson Brothers.