The correct way to say "they like something" in Spanish can depend on the subject being referred to.
- A ustedes les gusta. - This means "You all (formal) like something."
- A ellos les gusta. - This means "They (masculine or mixed group) like something."
- A él le gusta. - This means "He likes something."
- A vosotros os gusta. - This means "You all (informal, used in Spain) like something."
To specifically refer to "they," you would use A ellos les gusta. If you are including a group that is exclusively female, you would say A ellas les gusta.
In summary, A ellos les gusta is the correct choice if you want to say "they like something."