A club.
I believe that would be an interest group.
A clique
A club, or something similar.
answer is club and do not change it 'cos its right
People join interest groups because they are strongly motivated by the group's goals or, perhaps, they believe they can exercise power within the group that they would not otherwise have. Groups also entice people to join them by offering group benefits or even by punishing those who do not join.
CLUB
to have a voice in the government
No it is not a cool group. It is not a good idea to join any group because it may be cool. Rather join the ones that you actually have an interest in.
No, no one is ever required to join any interest group or other organization at any age during a person's lifetime.
State 4 reasons as to why people join group?
To gain more knowledge on the subject of interest - and share their knowledge with others.