Final answer:
The correct indirect object pronoun missing for the blank is 'les'.
Step-by-step explanation:
The correct option missing for the blank in the given sentence is les. The sentence should be '¿A ustedes les gusta celebrar el aniversario con los hombres de la familia?'. The indirect object pronoun 'les' is used to refer to 'ustedes' (you all) in Spanish.
Learn more about Indirect object pronouns in Spanish