score:4
I am not sure if what you are looking for exists. In these festivals you will usually have three groups. You can try joining one of them:
Often these festivals rely on volunteers for some management work in place> Welcoming visitors, etc. I have done some search and found out that for Santa Maria da Feira they actually have this type of role as well:
https://cm-feira.pt/noticias/-/noticias/NoticiasListagemPortlet_INSTANCE_lJ34mnXDbbBj/detail/2223992
You can enroll and wait to be accepted.