I believe that you need to make an API Request.
Do you know the TMDb API?
Do you have an API Key?
Do you know how to use it?

I tried making a request, but i can't get it to return only the actors. I have an API Key, but i do not know how to use it to get only what i want. That's why i were asking if someone have been successful in that matter. (And preferable what they did.)

In order for someone to help you with API Request questions, it is critical that you post here the API Request you are using.
Remember to replace your Key with THE_KEY , or something like that.

This will facilitate our conversation.
It is easier to explain.
Probably what you want is something like this:

https://api.themoviedb.org/3/movie/550/credits?api_key=THE_KEY

See here https://developers.themoviedb.org/3/movies/get-movie-credits
Click the Try it out tab. And build your API Request.